AN: Well, this ended up being one of the longest chapters I've written so far! It's one of my favourite stories so that doesn't really surprise me, but I was a good 1000 words off when I estimated the word count xD

I hope you enjoy this as much as I loved putting it together!

Chapter 8: The Unicorn and the Wasp

The Doctor stepped out of the Tardis and inhaled deeply.

"Oh, smell that air. Grass and lemonade. And a little bit of mint. A hint of mint. Must be somewhere in the nineteen twenties."

Donna raised an eyebrow at him. "You can tell what year it is just by smelling?"

"Oh, yeah."

Eris scoffed, gesturing through the gap in the bushes.

"Or maybe that big vintage car coming up the drive gave it away."

They watched as the sleek open-topped car ground to a halt on the gravel in front of the house, sounding its horn.

Two men in servants' uniform scurried out of the front door, one gesturing to the other.

"The Professor's baggage, Richard. Step lively."

The driver stepped out of the car and removed his goggles, grinning as the butler nodded politely.

"Good afternoon, Professor Peach."

"Hello, Greeves, old man."

A young man on a bicycle rode up, kicking the stand down so that it rested upright. He wore the distinctive white collar of a member of the clergy. The Professor turned to greet him.

"Ah, Reverend."

"Professor Peach. Beautiful day. The Lord's in his heaven, all's right with the world."

Greeves nodded to the new arrival. "Reverend Golightly. Lady Eddison requests you make yourselves comfortable in your rooms. Cocktails will be served on the lawn from half past four."

The Professor patted the younger man on the back. "You go on up. I need to check something in the library."

"Oh?"

"Alone."

The Reverend rolled his eyes teasingly.

"It's supposed to be a party. All this work will be the death of you."

Pressed up against the bushes so they could watch without being noticed, Donna beamed.

"Never mind Planet Zog. A party in the nineteen twenties, that's more like it!"

The Doctor sighed. "The trouble is, we haven't been invited. Oh, I forgot." And he waggled the psychic paper in the air. "Yes, we have!"

Comfortably sequestered away in the library, Professor Peach could hardly believe what he was reading. His research had taken a turn he had imagined, but never expected.

"I was right. Kept secret all these years. It's unbelievable. But why didn't they ask? Heavens!"

He heard the door creak behind him, and quickly hid the papers behind his back. He relaxed at the sight of the person who appeared.

"Oh, it's you. I was just doing a little research." He blinked in confusion as they raised an arm."I say, what are you doing with that lead piping?"

And then before his very eyes, something happened that seemed to have come out of a nightmare. The figure before him warped, bulging and shifting into something horrific. A droning buzz filled the room.

"But that's impossible. Oh, no!"

The pipe swung downwards.

Checking the time again, the Doctor knocked on the Tardis door, groaning.

"Come on you two! We'll be late for cocktails."

Donna led the way out of the ship, having changed into a knee-length black dress covered in intricate beading in shades of orange, brown and gold.

"What do you think? Flapper or slapper?"

He looked her up and down for a moment before smiling. "Flapper. You look lovely."

Eris stepped out next, tugging at the hem of the skirt with a frown. Her dress was Tardis blue with silver detailing, and she'd twisted her hair into a braided low bun, framing it with a string of silver beads.

"I wish it was acceptable for upper-class women to wear suits in this era. I hate this outfit."

Hoping to broker a bit of peace between them, he reached back into the Tardis and grabbed a little beaded cardigan from the hat stand. He'd wondered why the ship had left it there earlier - now, he was glad for it. Clearly, she wanted them to make up too.

"Here. I know it's probably the skirt that's bothering you most, and I can't really fix that, but this might help you feel a bit less exposed at the top."

She shrugged it on, visibly relaxing as the soft fabric covered her.

"Thanks. It's better than nothing."

She smiled back, and he felt his hearts leap. They were making progress.

As they made their way towards the little gathering on the lawn, one of the footmen started a record as a middle-aged Indian woman - clearly the most senior of the servants - ordered her team about.

"Look sharp. We have guests."

The Doctor grinned. "Good afternoon."

The footman approached them. "Drinks, sir? Ma'am?"

Donna eyed the young man with interest - he was rather attractive. "Sidecar, please."

Slowly relaxing into herself, Eris smiled politely. "A gin rickey for me, please."

The Doctor decided that avoiding alcohol was probably for the best.

"And a lime and soda, thank you."

As the footman left to fetch what they wanted, Greeves introduced their host.

"May I announce Lady Clemency Eddison."

She was a petite older woman, and she came to visit them first.

"Lady Eddison."

"Forgive me, but who exactly might you be, and what are you doing here?"

"I'm the Doctor. This is my daughter, Miss Eris Smith. And this is Miss Donna Noble, of the Chiswick Nobles."

Donna dropped into a curtsey. "Good afternoon, my lady. Topping day, what? Spiffing. Top hole."

He lowered his voice, "No, no, no, no, no. No, don't do that. Don't." before returning to his normal volume as he produced the psychic paper. "We were thrilled to receive your invitation, my lady. We met at the Ambassador's reception."

There was a flash of visible confusion across her face, but she recovered it well, soon returning to the polite friendly expression that was natural to the British upper class.

"Doctor, how could I forget you? But one must be sure with the Unicorn on the loose."

"A unicorn? Brilliant. Where?"

"The Unicorn. The jewel thief? Nobody knows who he is. He's just struck again. Snatched Lady Babbington's pearls right from under her nose."

Donna and Eris exchanged glances and muttered to each other.

"Well, what a funny place to wear pearls."

Greeves returned to the group, accompanied by two men, clearly father and son. The older was in a wheelchair and was being pushed by the younger.

"May I announce Colonel Hugh Curbishley, the Honourable Roger Curbishley."

Lady Eddison smiled sweetly.

"My husband, and my son."

"Forgive me for not rising. Never been the same ever since that flu epidemic back in eighteen."

Roger parked his father in a shady spot, and came over to greet the trio first.

"My word, you are a super lady."

Donna blushed. "Oh, I like the cut of your jib. Chin, chin."

He turned to Eris, and kissed the back of her hand. "And you, my dear. It's a pleasure."

She shot him a look, which he returned. "Oh, the pleasure is all mine."

Concerned that this was a bit of flirting too obvious for the nineteen twenties, the Doctor offered the man a handshake.

"Hello. I'm the Doctor."

"How do you do?"

"Very well."

As he stepped back to accept a drink, Eris whispered discreetly.

"Ten quid says he's blue as anything."

The others frowned at her, baffled, as she watched the footman pass Roger the glass.

"Your usual, sir?"

"Ah. Thank you, Davenport. Just how I like it."

Donna had a more pressing question on her mind.

"How come she's an Eddison, but her husband and son are Curbishleys?"

The Doctor shrugged. "The Eddison title descends through her. One day Roger will be a lord."

Greeves appeared again, nodding to a very attractive brunette.

"Robina Redmond."

Lady Eddison whispered to them as she started making her introductions.

"She's the absolute hit of the social scene. A must. Ah, Miss Redmond."

"Spiffing to meet you at last, my lady. What super fun."

The next person to arrive was the church man they had seen earlier.

"Reverend Arnold Golightly."

She clasped his hands in hers. "Ah, Reverend. How are you? I heard about the church last Thursday night. Those ruffians breaking in."

Her husband looked up at the tall man. "You apprehended them, I hear."

The Reverend nodded. "As the Christian Fathers taught me, we must forgive them their trespasses. Quite literally."

Roger scoffed. "Some of these young boys deserve a descent thrashing."

At his elbow, the footman spoke quietly. "Couldn't agree more, sir."

They exchanged a look for just a little longer than was typical, and Eris grinned.

"I told you so."

Donna realised what she'd been getting at, and sighed.

"Typical. All the decent men are on the other bus."

"Or Time Lords." The Doctor put his hands in his pockets, completely ignoring the looks of amused disgust his friends shot at each other.

Roger shifted away from the footman slightly and changed the subject of conversation.

"Now, my lady. What about this special guest you promised us?"

Lady Eddison gestured to the woman approaching them across the lawn, and the majority of the guests burst into applause. "Here she is. A lady who needs no introduction."

"No, no, please, don't. Thank you, Lady Eddison. Honestly, there's no need."

She approached the three people who weren't clapping first and extended a hand.

"Agatha Christie."

Donna raised an eyebrow. "What about her?"

"That's me."

"No. You're kidding."

The Doctor accepted the hand, shaking vigorously as he chattered.

"Agatha Christie. I was just talking about you the other day. I said, I bet she's brilliant. I'm the Doctor. This is my daughter Eris, and this is Donna. Oh, I love your stuff. What a mind. You fool me every time. Well, almost every time. Well, once or twice. Well, once. But it was a good once."

Eris huffed. "For goodness sake, will you let her speak? One can't exactly hold a conversation if the other person won't let them get a word in edgeways."

Agatha looked between him and the ginger woman with some amusement. She could sense some tension coming from the young brunette, and figured that was a situation best left alone.

"You make a rather unusual couple."

Again, Eris couldn't stop herself from laughing at the looks on their faces as they tried to correct her.

"Oh, no, no, no, no. We're not married."

"We're not a couple."

She smirked. "Well, obviously not. No wedding ring."

"Oh. Oh, you don't miss a trick."

She directed her next comment at Donna. "I'd stay that way if I were you. The thrill is in the chase, never in the capture."

Lady Eddison took her by the arm, keen to get her talking to some of her family.

"Mrs Christie, I'm so glad you could come. I'm one of your greatest followers. I've read all six of your books. Er, is, er, Mister Christie not joining us?"

"Is he needed? Can't a woman make her own way in the world?"

From his chair, Colonel Curbishley wagged his finger in mocking remonstrance.

"Don't give my wife ideas."

Roger leant against the back of his father's chair.

"Now Mrs Christie, I have a question. Why a Belgian detective?"

She shrugged. "Belgians make such lovely buns."

Polite laughter arose, and the young man continued.

"I say, where on Earth's Professor Peach? He'd love to meet Mrs Christie."

The Reverend looked thoughtful. "Said he was going to the library."

Lady Eddison gestured to the housekeeper.

"Miss Chandrakala, would you go and collect the Professor?"

"At once, Milady."

Spotting something on the front page that caught her eye, Eris tapped the top of the Colonel's newspaper.

"Sorry, but may I borrow this for just a moment?"

"Of course, my dear, take it. I was very nearly finished anyway."

"Thank you."

She held the paper out to the others and lowered her voice.

"Do you see it?"

The Doctor frowned at it for a second, before noticing.

"Oh. The date on this newspaper."

Donna shrugged. "What about it?"

"It's the day Agatha Christie disappeared. She'd just discovered her husband was having an affair."

"You'd never think to look at her, smiling away."

"Well, she's British and moneyed. That's what they do. They carry on. Except for this one time. No one knows exactly what happened. She just vanished. Her car will be found tomorrow morning by the side of a lake. Ten days later, Agatha Christie turns up in a hotel in Harrogate. Said she'd lost her memory. She never spoke about the disappearance till the day she died, but whatever it was…" He trailed off.

"It's about to happen."

"Right here, right now."

Perfectly timed, Miss Chandrakala ran from the front doors of the house towards them, waving her hands in the air and crying out.

"The Professor! The library! Murder! Murder!"

They had all hurried up to the library, led by the Doctor once he knew which way to go. As he dropped to his knees beside the body, he could hear the gasp of the butler as he saw what had befallen one of the people he had been meant to look after.

"Oh, my goodness."

He glanced over to Eris as she rifled through the papers on the desk. "Bashed on the head. Blunt instrument. Watch broke as he fell. Time of death was quarter past four."

Donna picked up a length of metal pipe and passed it over.

"A bit of pipe. Call me Hercule Poirot, but I reckon that's blunt enough."

Agatha stopped by the fireplace, discreetly sifting through the burnt papers in the grate until she could retrieve the fragment that had caught her eye and tuck it away somewhere safe. She didn't realise that two of the other three people in the room had noticed her movement.

Eris sighed, replacing the papers.

"Nothing worth killing for in that lot. Dry as dust. So we still don't have a motive."

Looking between her friends, Donna pulled a face.

"Hold on. The body in the Library? I mean, Professor Peach, in the library, with the lead piping? This has got to be some kind of set up."

They were interrupted by the forced entry of the other guests, who gathered in the doorway gasping and looking pale.

"Let me see."

"Out of my way."

"Gerald?"

"Saints preserve us."

"Oh how awful."

Agatha straightened up, trying to be the voice of reason. "Someone should call the police."

Digging out the psychic paper, the Doctor flashed it at them once again.

"You don't have to. Chief Inspector Smith from Scotland Yard, known as the Doctor. Miss Noble and Miss Smith are the plucky young girls who help me out."

Lady Eddison put a hand to her chest. "I say."

"Mrs Christie was right. Go into the sitting room. I will question each of you in turn."

She moved to usher them out of the door. "Come along. Do as the Doctor says. Leave the room undisturbed."

As she vanished down the corridor, Donna rounded on him.

"The plucky young girl who helps me out?"

"No policewomen in 1926."

"I'll pluck you in a minute. Why don't we phone the real police?"

"Well the last thing we want is PC Plod sticking his nose in, especially now I've found this." He dropped to his knees, scraping at a blob of yellowy gunge with the tip of a pencil.

"Morphic residue."

"Morphic? Doesn't sound very 1926."

"It's left behind when certain species genetically re-encode."

She scoffed. "The murderer's an alien?"

Standing by the door to ensure his actions weren't observed, Eris shrugged.

"It usually is, when he's around."

Her tone made him frown a little. She'd been keeping to herself for a while now, not quite cold-shouldering him but definitely pulling away. Her jokes had become self-deprecating or turned into snide digs. He assumed it was related to Jenny's death, which had torn him apart too. He just wished he knew what was going on in her head so that he could help.

"Which means one of that lot is an alien in human form."

Donna rolled her eyes. "Yeah, but think about it. There's a murder, a mystery, and Agatha Christie."

"So? Happens to me all the time."

"No, but isn't that a bit weird? Agatha Christie didn't walk around surrounded by murders. Not really. I mean, that's like meeting Charles Dickens and he's surrounded by ghosts at Christmas."

"Well…"

"Oh, come on! It's not like we could drive across the country and find Enid Blyton having tea with Noddy. Could we? Noddy's not real. Is he? Tell me there's no Noddy."

He looked up at her, very serious.

"There's no Noddy."

After a further sweep uncovered nothing else of use, the three of them descended the stairs, Donna still chattering on.

"Next thing you know, you'll be telling me it's like Murder On The Orient Express, and they all did it."

Agatha appeared in the doorway beside them. "Murder on the Orient Express?"

"Ooh, yeah. One of your best."

Dropping her voice - and trying to keep the grin out of her tone - Eris muttered to her.

"But not yet."

The author looked thoughtful. "Marvellous idea, though."

"Yeah. Tell you what. Copyright Donna Noble, okay?"

The Doctor got them back on topic. "Anyway. Agatha, Eris and I will question the suspects. Donna, you search the bedrooms. Look for clues." He switched to a whisper briefly, "Any more residue." and then returned to normal volume as he passed over a magnifying glass. "You'll need this."

She looked at it like it was about to bite her.

"Is that for real?"

"Go on. You're ever so plucky."
She started back up the stairs, and Eris moved to follow her.

"I'll go with Donna. Two pairs of eyes are better than one, and all that."

His shoulders sagged with visible disappointment as they left, and for a moment Agatha felt sorry for him. Clearly, something had happened to upset the relationship between them, and they were both taking it hard. Then, he turned to her and clapped his hands together.

"Right then. Solving a murder mystery with Agatha Christie. Brilliant."

She scoffed. "How like a man to have fun while there's disaster all around him."

"Sorry. Yeah."

"I'll work with you, gladly, but for the sake of justice, not your own amusement."

"Yeah."

The two of them commandeered the sitting room for conducting interviews; the Doctor took the lead in questioning while Agatha took notes and watched for any non-verbal tells.

"Now then, Reverend. Where were you at a quarter past four?"

"Let me think. Why yes, I remember. I was unpacking in my room."

"No alibi, then. You were alone?"

He laughed politely. "Well with the Lord, one is never truly alone."

Next, they spoke to Roger.

"And where were you?"

"Let me think. I was…" In comparison to the Reverend's cool calmness, he was visibly jittery. "Oh, yes. I was taking a constitutional in the fields behind the house. Just taking a stroll, that's all."

"Alone?"

"Oh, yes, all alone. Totally alone. Absolutely alone. Completely. All of the time. I wandered lonely as the proverbial cloud. There was no one else with me. Not at all. Not ever."

The jabbering self-defense combined with the pretty shade of pink that was quickly flooding his cheeks made it very obvious that he was lying. But the reasoning behind it was also rather obvious, and he didn't keep the young man there any longer than he had to.

The next person to be questioned was Miss Redmond, who sat demurely through the entire experience with a slight air of, 'I don't see why this is my problem'.

"And where were you?"

"At a quarter past four… Well, I went to the toilet when I arrived, and then er… Oh, yes, I remember. I was preparing myself. Positively buzzing with excitement about the party and the super fun of meeting Lady Eddy."

He raised an eyebrow. "We've only got your word for it."

Her response was fast. "That's your problem, not mine."

Next was the Colonel - neither Agatha nor the Doctor thought he was likely to have anything to do with it, given his condition, but it was worth speaking to everyone just in case they had seen something.

"And where were you, sir?"

"Quarter past four? Dear me, let me think. Ah, yes, I remember. I was in me study, reading through some military memoirs. Fascinating stuff." His eyes started to drift, becoming unfocused, and they began to suspect that that hadn't been what he'd been recalling. "Took me back to my days in the army. Started reminiscing. Mafeking, you know. Terrible war." A sort of smile began to appear, and the Doctor sighed.

"Colonel, snap out of it."

"I was in me study…"

"No, no, no. Right out of it."

"Oh, sorry. Got a bit carried away there."

Lady Clemency sat there, practically vibrating with stress under their shared gaze.

"And where were you at a quarter past four, my lady?"

"Now, let me see. Yes, I remember. I was sitting in the Blue Room, taking my afternoon tea. It's a ritual of mine. I needed to gather strength for the duty of hostess. I then proceeded to the lawn where I met you, Doctor, and I said, who exactly might you be and what are you doing here? And you said, I am the Doctor and this is my daughter Eris, and this is Miss Donna Noble."

Getting a little bored of the account, he waved a hand.

"Yes, yes. You can stop now. I was there for that bit."

"Of course." She hiccuped a little, and both detectives suspected she'd been drinking something a little stronger than tea earlier. "Excuse me."

Done with interviewing the guests and residents, the Doctor and Agatha paced up and down the room in parallel.

"No alibis for any of them. The Secret Adversary remains hidden. We must look for a motive." She put an accent on. "Use ze little grey cells."

Throwing himself into a chair, he grinned. "Oh, yes, little grey cells. Good old Poirot. You know, I've been to Belgium. Yeah. I remember I was deep in the Ardennes, trying to find Charlemagne. He'd been kidnapped by an insane computer."

He was visibly distracted, and she snapped her fingers in front of his face.

"Doctor? Doctor."

"Sorry."

"Charlemagne lived centuries ago."

"I've got a very good memory."

"For such an experienced detective, you missed a big clue."

He snorted. "What, that bit of paper you nicked out the fire? Even Eris saw you do it."

"You were looking the other way."

"Yeah, but we saw you reflected in the glass of the bookcase."

"You crafty man. This is all that was left."

She showed him the charred fragment. The only remaining legible thing was the word '...aiden'. It was difficult to tell how the word started, due to the amount of fire damage.

"What's that first letter? N or M?"

"It's an M. The word is maiden."

"Maiden!" He shouted, and she put a hand to her chest in shock. "What does that mean?"

She shook her head, irritated. "So. We're still no further forward. Our Nemesis remains at large. Unless Miss Noble and your daughter have found something."

After a few fruitless room checks, they hit the jackpot - a locked door. They stood around it, fiddling with the handle for a short time before being startled by the appearance of Greeves.

"You won't find anything in there."

Trying to hide just how much he'd surprised her, Donna put on her most authoritative tone.

"How come it's locked?"

"Lady Eddison commands it to be so."

"And I command it to be otherwise. Scotland Yard. Pip, pip."

Clearly reluctant, he found the relevant key on the ring and unlocked it, eyeing them both with distrust.

Eris glanced into the dusty chamber and frowned. "Why was it locked in the first place?"

He paused, then responded curtly.

"Many years ago, when my father was butler to the family, Lady Eddison returned from India with malaria. She locked herself in this room for six months until she recovered. Since then, the room has remained undisturbed."

The curtains were drawn, casting shadows over the whole room. It was relatively empty: it's only furniture was a set of simple drawers and a wardrobe, and a bed covered with a plain bedspread. A teddy bear sat at the top of the bed, just in front of the pillows.

"There's nothing in here."

"How long's it been empty?"

He thought before answering. "Forty years."

"Why would she seal it off? All right, we need to investigate. You just… buttle off."

As he left, not entirely convinced that letting them in was a good idea, they went in and closed the door behind them. Donna glanced over at Eris as she searched the chest of drawers.

"How did you know Roger was gay, earlier?"

"Ah, it was the look he gave me. Us queer folk are very good at spotting each other."

"Wait, so you… but I thought… what about that Ross bloke from UNIT?"

She grinned. "Oh Donna, I'll flirt with any adult - of any species - if I get the chance. Life's far more fun that way."

She opened her mouth to ask something else, then stopped as a faint buzzing sound grew louder behind her. It seemed to be coming from the curtains, and she couldn't help but smile.

"1926, they've still got bees. Oh, what a noise. All right, busy bee, I'll let you out. Hold on, I shall find you with my amazing powers of detection."

Raising the magnifying glass, she made a big show of scanning the area for clues before tugging the curtains open. But as she did so, she realised they were in terrible danger. For outside the window was a colossal wasp with a sting longer than her arm, lining up to ram the window. The glass shattered as it collided and entered the room, and she took a step back.

"That's impossible."

Eris grabbed her and pushed her back, putting herself in the wasp's path and keeping it distracted as Donna called for help.

"Doctor!"

It was blocking their only way out, and a thought hit Eris with a flash.

"Donna, throw me the magnifying glass!"

She did so, and watched as the other girl held it up, focusing the bright light onto the insect. It writhed in pain, cringing away from the bedroom door and giving Donna enough space to leg it out. She managed to open the door and get out, but Eris had no way of getting past the creature.

"Close the door, now! Go while you can!"

Realising that she didn't really have another choice, she closed the door, hoping the brunette had a plan to keep herself alive until help could get there.

Hearing footsteps on the stairs, Donna cried out.

"Doctor!"

The wasp's sting slammed through the wood of the door, splintering the material around it. Seconds later, the Doctor and Agatha arrived on the landing, looking at her in concern.

"What is it, what's happened?"

"It's a giant wasp."

"What do you mean, a giant wasp?"

"I mean, a wasp that's giant."

Agatha tutted. "It's only a silly little insect."

"When I say giant, I don't mean big, I mean flipping enormous! Look at its sting!" She moved to show them - a two-foot long spike that was wedged firmly in the doors, glistening stickily. And her next words confirmed his worries. "And Eris was still in there when that happened. It's been very quiet since."

"Let me in there. Now."

The door was jammed in the frame, and he slammed his shoulder against it repeatedly until it budged. He burst in, but there was nothing more of the large insect that had been there.

"It's gone. Buzzed off."

Agatha reached out to the sting, mesmerised. "But that's fascinating-"

"Don't touch it. Don't touch it. Let me…" Using the pencil he'd borrowed before, he scooped some of the thick goo on the sting into a test tube. "Giant wasp. Well, tons of amorphous insectivorous lifeforms, but none in this galactic vector."

"I think I understood some of those words. Enough to know that you're completely potty."

A groan from the other side of the room made them turn, and Donna rounded the end of the bed. "Eris! Are you ok?"

He joined her in time to see his daughter struggling to sit upright, a deep scratch on her temple slowly healing. Her eyes were slightly out of focus.

"Oh, my head. I don't…"

He put an arm around her back and helped her up. "What happened?"

"Not sure. I tried to blind it with the magnifying glass, but it must have caught me when it started thrashing. I didn't see it fly away, I'm sorry."

"Hey, it's alright. We'll find it again. I'm just glad you're safe."

"Yeah, well. Can't do anything right these days."

Sensing that things could devolve into an argument, Donna stepped in.

"Lost its sting, though. That's something, right? That makes it defenceless, doesn't it?"

He shook his head. "Oh, a creature this size? Got to be able to grow a new one."

Agatha huffed. "Can we return to sanity? There are no such things as giant wasps."

"Exactly. So. The question is, what's it doing here?"

A scream from outside made them turn and run, following the sound. They made it outside, following the gravel pathway until they came across the prone form of Miss Chandrakala. Large chunks of stone surrounded her, and quick glance upwards at the roof of the house showed a gap where a gargoyle should have been. A line of blood trailed from the corner of her mouth.

She was still alive - but only just. As the four of them reached her, she took Agatha's hand,

"The poor little child."

She wheezed a little, then her chest fell still. They had come too late to save her. A buzzing from above made them look upwards. There was the wasp - brand new sting and all.

"There! Come on!"

It flew inside the house, and they legged it back inside.

As they went back up the stairs, Eris stumbling a little as the dizziness clung to the edges of her brain. Donna managed a laugh as she grabbed the girl's elbow.

"Hey, this makes a change. There's a monster, and we're chasing it."

Agatha still wasn't entirely convinced. "It can't be a monster. It's a trick. They do it with mirrors."

They came to a halt opposite the wasp. It hovered in front of them, buzzing threateningly.

"By all that's holy."

He stepped forwards a little, hands out. "Oh, but you are wonderful. Now, just stop. Stop there."

It lunged, scraping the paper from the walls with it's sharp point.

"Oi, fly boy." Donna held up the magnifying glass, very glad she'd retrieved it, and it retreated at the memory of the pain the object had caused it last time.

He followed it through the corridors. "Don't let it get away! Quick, before it reverts back to human form." The group broke into a corridor - all the doors were closed. "Where are you? Come on. There's nowhere to run. Show yourself!"

Every door swung open and someone stepped out, looking bewildered at the intrusion.

He groaned. "Oh, that's just cheating."

They gathered everyone in the drawing room and broke the news of Miss Chandrakala's death - naturally, the news hit them hard. Especially Lady Eddison.

"My faithful companion, this is terrible."

The footman put a hand on her wrist. "Excuse me, my lady, but she was on her way to tell you something."

"She never found me. She had an appointment with death instead."

Watching from the other end of the room, the Doctor watched everyone closely. "She said, the poor little child. Does that mean anything to anyone?"

The Colonel sniffed. "No children in this house for years. Highly unlikely there will be." He eyed his son knowingly, but the boy kept his gaze on the patterns of the carpet.

Dabbing at her eyes, the lady of the house looked pleadingly at Agatha. "Mrs Christie, you must have twigged something. You've written simply the best detective stories."

Perched on the arm of a chair, the Reverend spoke mildly. "Tell us, what would Poirot do?"

She looked a little flustered, and the Colonel banged a hand down on the arm of his wheelchair.

"Heavens sake. Cards on the table, woman. You should be helping us."

"But, I'm merely a writer."

Robina eyed her. "But surely you can crack it. These events, they're exactly like one of your plots."

Donna put a hand on the older woman's arm, trying to reassure her.

"That's what I've been saying. Agatha, that's got to mean something."

She brushed her off. "But what? I've no answers. None. I'm sorry, all of you. I'm truly sorry, but I've failed. If anyone can help us, then it's the Doctor, not me."
And she swept out of the room, heading for the outside. Exchanging looks, Donna and Eris followed.

She had retreated to a little wrought iron gazebo just behind the house, and she didn't look best pleased to see them.

"I'm sorry, but I'd rather be on my own for a little while."

Eris sat down on the other end of the bench, leaning back against the wall. "I could do with the fresh air, to be honest. My head is still swimming a bit."

Donna sat a little closer to her, and went for a different tactic.

"Do you know what I think? Those books of yours, one day they could turn them into films. They could be talking pictures."

Agatha frowned. "Talking pictures? Pictures that talk? What do you mean?"

"Oh, blimey, I've done it again."

Eris pulled a face. "Yeah, bit early for that. Nice try though."

The author shook her head. "I appreciate you trying to be kind, but you're right. These murders are like my own creations. It's as though someone's mocking me, and I've had enough scorn for one lifetime."

Donna shrugged. "Yeah. Thing is, I had this bloke once. I was engaged. And I loved him, I really did. Turns out he was lying through his teeth. But do you know what? I moved on. I was lucky. I found the Doctor. It's changed my life. There's always someone else."

"I see. Is my marriage the stuff of gossip now?"

The tension in her tone was audible, and the girls looked a little awkward.

"No, I just… Sorry."

"No matter. The stories are true. I found my husband with another woman. A younger, prettier woman. Isn't it always the way?"

"Well, mine was with a giant spider, but, same difference."

"You three talk such wonderful nonsense. I've never heard anything like it."

"Agatha, people love your books. They really do. They're going to be reading them for years to come."

"If only. Try as I might, it's hardly great literature. Now that's beyond me. I'm afraid my books will be forgotten, like ephemera."

Eris sat up straight suddenly, an odd look on her face. "Wait. Look at things for a second, really look. Doesn't something seem… wrong?"

Agatha squinted for a moment, before nodding.

"Yes, look there. What's that? Those flowerbeds were perfectly neat earlier. Now some of the stalks are bent over."

They moved over to the spot she'd pointed out and looked through the rumpled stalks, retrieving a small leather case. As she turned it over in her hands, Donna nudged her gently.

"There you go. Who'd ever notice that? You're brilliant."

They took the case inside to show the Doctor. He'd taken himself into a side room to let the family and their guests deal with their emotions alone for now - and he was very impressed by the contents of the object.

"Ooo. Someone came here tooled up. The sort of stuff a thief would use."

Agatha nodded, having already worked out what that meant. "The Unicorn. He's here."

Eris hummed thoughtfully. "The Unicorn and the Wasp. Now that would make a good book title. Or a movie."

Greeves came in with a tray. "Your drinks, ladies. Doctor."

"Very good, Greeves."

He left. Eris moved to take a sip from her glass, then put it down again. Alcohol was probably not the best idea after a head injury.

Donna leant against the mantel. "How about the science stuff. What did you find?"

The Doctor took a long gulp from his drink before answering.

"Vespiform sting. Vespiforms have got hives in the Silfrax galaxy."

Agatha huffed. "Again, you talk like Edward Lear."

"But for some reason, this one's behaving like a character in one of your books."

Donna put on her most coaxing tone. "Come on, Agatha. What would Miss Marple do? She'd have overheard something vital by now, because the murderer thinks she's just a harmless old lady."

"Clever idea. Miss Marple? Who writes those?"

"Er… copyright Donna Noble. Add it to the list."

A frown crossed his face. "Donna."

"Okay, we could split the copyright."

"No. Something's inhibiting my enzymes. Argh! I've been poisoned!" He doubled up in pain, and the others moved to make sure he was alright. Eris took the glass and sniffed it, grimacing as she passed it over to Agatha.

"That's definitely been spiked. Not sure what with though."

Donna helped him to his feet - he clearly wanted to get up and go somewhere - and struggled to support him as he convulsed again. "What do we do? What do we do?"

Examining the drink, Agatha nodded.

"Bitter almonds. It's cyanide. Sparkling Cyanide."

He staggered along to the kitchen - still moving fast enough that the others struggled to keep up with him - and startled all of the staff as he burst through the door.

"Ginger beer!"

"I beg your pardon?"

"I need ginger beer."

"The gentleman's gone mad."

He managed to find a bottle of ginger beer and drank half of it in one gulp, pouring the rest over his head. Agatha looked at him, concerned.

"I'm an expert in poisons. Doctor, there's no cure. It's fatal."

As he shook his head, little droplets of ginger beer flew across the room.

"Not for me. I can stimulate the inhibited enzymes into reversal. Protein. I need protein."

Eris grabbed a packet from the side and tossed it to him.

"Walnuts?"

"Perfect." He filled his mouth with them, chewing as quickly as he could while he tried to mime what he needed next. Donna was the only person watching his hand movements - and they weren't exactly the easiest of things to interpret.

"I can't understand you. How many words? One. One word. Shake. Milkshake. Milk? Milk? No, not milk? Shake, shake, shake. Cocktail shaker. What do you want, a Harvey Wallbanger?"

He swallowed painfully and managed to choke out around what was left, "Harvey Wallbanger?"

"Well, I don't know!"

"How is Harvey Wallbanger one word?"

Agatha had joined Eris in the search for helpful items. "What do you need, Doctor?"

"Salt. I was miming salt. It's salt. I need something salty."

Spotting a jar on the side, Donna handed it over. "What about this?"

"What is it?"

"Salt."

"No, too salty."

"Oh, that's too salty." She rolled her eyes, throwing her hands in the air.

Agatha had found something else. "What about this?"

"What's that?"

"Anchovies."

He downed the contents and started miming something new. Again, Donna didn't have much to go on.

"What is it? What else? It's a song? Mammy? I don't know. Camptown Races?"

"Camptown Races?"

"Well, all right then, Towering Inferno."

The scene would have been far funnier if his life wasn't in imminent danger.

"It's a shock. Look, shock. I need a shock."

"But there's nothing electric in here!"

Grabbing her friend by the arm, Eris shot her an apologetic look.

"You might not enjoy this, Donna, but it'll have to do for now."

And she pushed the two of them together. Their lips collided, hard, and the kiss (for the people involved, anyway) felt like it lasted for years. Then he pulled backwards, stumbling a little as a plume of charcoal-y smoke bloomed from his mouth and nose, rising and then dissipating as his breath returned to normal.

"Detox. Oh my. I must do that more often." Then, he saw the look of disgust on Donna's face and backtracked as quickly as he could. "I mean, the detox."

Agatha felt like she was scraping her jaw off the floor as she looked at the man, now completely healthy.

"Doctor, you are impossible. Who are you?"

The two of them suspected that Donna was rather proud of herself, at the moment. The three of them had gone to one of the smaller drawing rooms to allow the Doctor to finish recovering from his experience. But they had only been in the room a few minutes when she had got to her feet, hands on hips.

"Right. I'm off to have another look around, see if I can find any more clues. You know, little bottles of poison in anyone's rooms and all that. See you in a bit."
And before Eris could make her escape, she had left. So the two of them were at opposite ends of the room, staring at the floor awkwardly. They had clearly been left there in an attempt to get them to make up with each other properly. Sighing, the Doctor broke the silence.

"Are you angry with me?"

"No." Her voice was quiet, and she kept her head down.

"So what's bothering you?"

"Nothing."

"Don't lie to me, Eris." He came close to snapping at her, and took a deep breath. "Look, I'm not angry with you. Ok? I promise I'm not. But I am worried about you. You've not been yourself for the last few trips. Obviously I understand that you're upset about Jenny, and so am I-"

She scoffed, face twitching with anger, and he took a step closer to her.

"What is it? Please, just tell me. All I want to do is help."

"I should've noticed."

"Noticed what?"

"The gun!" She raised her voice, finally making eye contact with him - and he could see the tears gathering in her eyes. "I should've been watching Cobb, should've known he was stupid enough to take the shot! I should've been the one to move first so she didn't feel like she had to, it should've been me-"

He didn't let her finish the sentence. He rushed forwards and hugged her as tightly as he could possibly manage, rocking gently as he felt her break down, clinging to his coat.

"No. No, no, no. Don't put that on yourself. Please. Hey? I should've been watching Cobb too. I should've moved out of the way. Or shouted, or grabbed something as a shield, or anything. I promise you, it's not your fault. Or mine. It happened, and it was horrible, but there's nothing either of us could have done in that moment to stop it. Ok? Look at me."

She looked up, watery brown eyes meeting his.

"She'll always be part of us both. Sod blood, sod genes, that doesn't matter. She was ours, and we're never gonna forget her. Right?"

"Right."

He brushed the tears from her face and kissed the top of her head.

"So, are we ok?"

"I think so."

"Good." He grinned, tapped her on the nose, and started pacing the room. "Now, how are we going to work out who our buzzy little friend is, hmm? I strongly doubt Donna is going to find anything in any of the rooms."

Leaning against the nearest piece of furniture, a mischievous smile started to creep across her cheeks - and he was glad to see a little bit of her usual self coming back to life.

"How about you give them a taste of their own medicine?"

As night fell, and a storm rolled in, the hosts and their guests settled down for a candlelit dinner. The starter had been rather lovely, and as the soup course was set out, the Doctor's plan started to unfurl.

"A terrible day for all of us. The Professor struck down, Miss Chandrakala taken cruelly from us, and yet we still take dinner."

Lady Eddison nodded. "We are British, Doctor. What else must we do?"

"And then someone tried to poison me. Any one of you had the chance to put cyanide in my drink. But it rather gave my wonderful daughter an idea. One that I thought was quite genius."

The Reverend looked up at him, spoon halfway to his mouth. "And what would that be?"

"Well, poison. Drink up." Everyone froze, some having just had a mouthful of their meal and others with the spoon just at their lips. "I've laced the soup with pepper."

The only person who had kept eating - the Colonel - nodded appreciatively, continuing to consume it.

"Ah, I thought it was jolly spicy."

That ticked him off the list then, the Doctor thought. "But the active ingredient of pepper is piperine, traditionally used as an insecticide. So, anyone got the shivers?"

With a crash of thunder, the windows blew open; the wind extinguishing the candles and plunging them all into silhouetted darkness.

"What the deuce is that?"

Eris got to her feet, hands against the table. "Shhh. Listen, listen, listen, listen."

There was a buzzing sound bouncing from the walls.

Lady Eddison gasped. "No, it can't be."

Lightning illuminated the room for the briefest of moments, but nothing vecame visible.

Agatha started getting to her feet. "Show yourself, demon."

The Doctor put a hand out to her. "Nobody move. No, don't! Stay where you are."

With another flash of lightning, the wasp became visible.

"Out, out, out, out, out, out!"

Everyone scattered. The trio of time travellers, Agatha and Greeves backed into an alcove, the Doctor making sure the humans were behind him.

"Not you, Agatha. You've got a long, long life to live yet."

He moved to pull a sword from the wall, but someone switched the electric lights on - and the wasp had disappeared once again.

Aware of the panicking Greeves behind her, Donna mumbled under her breath.

"Well, we know the butler didn't do it."

"Then who did?" The Doctor whispered back.

On first glance, the only person in the room who had been seriously affected was the Colonel; his wheelchair had been tipped onto it's side. As those strong enough to get him upright did so, Lady Eddison gasped and clawed at her throat.

"My jewellery. The Firestone, it's gone. Stolen!"

And another, far more devastating loss was noticed. The young footman, unable to keep the pain out of his voice, stumbled forwards.

"Oh, Roger."

The man was face down in his soup bowl, a large knife jammed deep into his back. As Robina screamed, his mother staggered towards him, tears streaming.

"My son. Oh, my child!"

The Doctor, Agatha and Eris retreated to one of the sitting rooms, and were soon joined by Donna. The look on her face said it all.

"That poor footman. Roger's dead and he can't even mourn him. 1926? It's more like the dark ages."

Agatha sighed sadly. She too had noticed the looks shared by the pair. "Did you enquire after the necklace?"

"Lady Eddison bought it back from India. It's worth thousands."

Fingers steepled under his chin, the Doctor stared off into the distance. "This thing can sting, it can fly. It could wipe us all out in seconds. Why is it playing this game?"

"Every murder is essentially the same. They are committed because somebody wants something."

"What does a Vespiform want?"

"Doctor, stop it. The murderer is as human as you or I."

"You're right." He sat up straight. "Ah, I've been so caught up with giant wasps that I've forgotten. You're the expert."

"I'm not. I told you. I'm just a purveyor of nonsense."

"No, no, no, no, no, no, no. Because plenty of people write detective stories, but yours are the best. And why? Why are you so good, Agatha Christie? Because you understand. You've lived, you've fought, you've had your heart broken. You know about people. Their passions, their hope, and despair, and anger. All of those tiny, huge things that can turn the most ordinary person into a killer. Just think, Agatha. If anyone can solve this, it's you."

There were a few moments of silence as she pondered his words, before she got to her feet.

"Alright then. Let's end this."

The others had gathered in another of the rooms, waiting for the four of them to return. The Doctor opened up the discussion as Eris and Donna took seats by the wall behind him, sharing a bowl of nuts - after all, dinner had been cut short.

"I've called you here on this endless night, because we have a murderer in our midst. And when it comes to detection, there's none finer. Ladies and gentlemen, I give you, Agatha Christie."

Agatha nodded politely at him, and tried to sound as confident as she possibly could.

"This is a crooked house. A house of secrets. To understand the solution, we must examine them all. Starting with you, Miss Redmond."

The young woman in question blinked, startled. "But I'm innocent, surely?"

"You've never met these people, and these people have never met you. I think the real Robina Redmond never left London. You're impersonating her."

"How silly. What proof do you have?"

"You said you'd been to the toilet…"

Donna cut in, starting to enjoy things. "Oh, I know this. If she was really posh, she'd say loo."

Holding up the lockpicking kit, Agatha continued.

"Earlier today, Miss Smith, Miss Noble and I found this on the lawn, right beneath your bathroom window. You must have heard that Miss Noble was searching the bedrooms, so you panicked. You ran upstairs and disposed of the evidence."

"I've never seen that thing before in my life."

Lady Eddison leant forward in her chair. "What's inside it?"

"The tools of your trade, Miss Redmond. Or should I say, the Unicorn. You came to this house with one sole intention. To steal the Firestone."

With a roll of her eyes, 'Robina' dropped the accent and slipped back into something that was pure cockney. "Oh, all right then. It's a fair cop. Yes, I'm the bleeding Unicorn. Ever so nice to meet you, I don't think. I took my chance in the dark and nabbed it. Go on then, you knobs. Arrest me. Sling me in jail."

She tossed the necklace at the Doctor and shot a wink at Eris - who returned it with a smirk. Donna shot her friend a look, then asked,

"So, is she the murderer?"

"Don't be so thick. I might be a thief, but, well, I ain't no killer."

Agatha nodded. "Quite. There are darker motives at work. And in examining this household, we come to you, Colonel."

Sighing, the Colonel shifted. "Damn it, woman. You with your perspicacity. You've rumbled me."

And to the surprise of everyone else in the room, the man got to his feet, standing on slightly shaky legs. His wife's eyes widened.

"Hugh, you can walk. But why?"

"My darling, how else could I be certain of keeping you by my side?"

"I don't understand."

"You're still a beautiful woman, Clemency. Sooner or later some chap will turn your head. I couldn't bear that. Staying in the chair was the only way I could be certain of keeping you. Confound it, Mrs Christie, how did you discover the truth?"

Agatha had been standing there as wide eyed as the rest of them.

"Er, actually I had no idea. I was just going to say you're completely innocent."

"Oh. Oh…"

"Sorry."

"Well. Well, shall I sit down then?"

"I think you better had."

Stuffing another handful of peanuts into her mouth, Donna nodded towards him.

"So he's not the murderer."

"Indeed, not. To find the truth, let's return to this." The Firestone - a stunning purple jewel set in silver. "Far more than the Unicorn's object of desire. The Firestone has quite a history. Lady Eddison."

The woman in question had gone rather pale. "I've done nothing."

"You brought it back from India, did you not? Before you met the Colonel. You came home with malaria, and confined yourself to this house for six months, in a room that has been kept locked ever since, which I rather think means…"

"Stop, please."

Behind her, Eris nudged Donna in the ribs. "Hang on, six months? Surely that means she was-"

Agatha cut her off, hoping to deliver the blow a little more gently.

"I'm so sorry. But you had fallen pregnant in India. Unmarried and ashamed, you hurried back to England with your confidante, a young maid later to become housekeeper. Miss Chandrakala."

Now it was the Colonel's turn to look at his wife in shock.

"Clemency, is this true?"

"My poor baby. I had to give him away. The shame of it."

"But you never said a word."

"I had no choice. Imagine the scandal. The family name. I'm British. I carry on."

The Doctor folded his arms across his chest.

"And it was no ordinary pregnancy."

"How can you know that?"

"Excuse me Agatha, this is my territory."

He stepped forwards, taking centre stage. "But when you heard that buzzing sound in the dining room, you said, it can't be. Why did you say that?"

"You'd never believe it."

Agatha moved to lay a supportive hand on the woman's shoulder.

"The Doctor has opened my mind to believe many things."

"It was forty years ago, in the heat of Delhi, late one night. I was alone, and that's when I saw it. A dazzling light in the sky. The next day, he came to the house. Christopher, the most handsome man I'd ever seen. Our love blazed like a wildfire. I held nothing back. And in return he showed me the incredible truth about himself. He'd made himself human, to learn about us. He showed me his true shape. I loved him so much, it didn't matter. But he was stolen from me. 1885, the year of the great monsoon. The river Jumna rose up and broke its banks. He was taken at the flood. But Christopher left me a parting gift. A jewel like no other. I wore it always. Part of me never forgot. I kept it close, always."

Now sat down next to Eris, 'Robina' scoffed.

"Just like a man. Flashes his family jewels and you end up with a bun in the oven."

Agatha ignored her. "A poor little child. Forty years ago, Miss Chandrakala took that newborn babe to an orphanage. But Professor Peach worked it out. He found the birth certificate."

Donna wagged a finger as she passed the bowl over to her friend.

"Oh, that's maiden. Maiden name."

"Precisely."

"So she killed him?"

Lady Eddison bristled "I did not."

"Miss Chandrakala feared that the Professor had unearthed your secret. She was coming to warn you."

"Ah. So she killed her!"

"I did not!"

"Lady Eddison is innocent. Because at this point, Doctor…."

He jumped in. "Thank you. At this point, when we consider the lies and the secrets, and the key to these events, then we have to consider it was you, Donna Noble."

She pulled a face. "What? Who did I kill?"

"No, but you said it all along. The vital clue. This whole thing is being acted out like a murder mystery, which means it was you, Agatha Christie."

The author in question looked at him like he was mad. "I beg your pardon, sir?"

"So she killed them?"

He rolled his eyes. "No. But she wrote. She wrote those brilliant, clever books. And who's her greatest admirer? The moving finger points at you, Lady Eddison."

She scrunched her eyes closed. "Don't. Leave me alone."

"So she did kill them!"

"No! But just think. Last Thursday night, what were you doing?"

She shrugged. "I was I was in the library. I was reading my favourite Agatha Christie, thinking about her plots, and how clever she must be. How is that relevant?"

"Just think. What else happened on Thursday night?"

Nobody else came up with an answer, and Eris - whose arm had mysteriously disappeared behind the Unicorn's back - turned to look at the Reverend.

"Oh, of course."

There was a look of mild confusion on his face. "I'm sorry?"

The Doctor shrugged. "You said on the lawn, this afternoon. Last Thursday night, those boys broke into your church."

"That's correct. They did. I discovered the two of them. Thieves in the night. I was most perturbed. But I apprehended them."

"Really? A man of God against two strong lads? A man in his forties? Or, should I say forty years old, exactly?"

Lady Eddison was now so pale she was almost translucent. "Oh, my God."

"Your child, how old would he be now?"

"Forty. He's forty."

"Your child has come home."

The Reverend scoffed, but there was a note of panic in his eyes. "Oh, this is poppycock."

"Oh? You said you were taught by the Christian Fathers, meaning you were raised in an orphanage. You found those thieves, Reverend, and you got angry. A proper, deep anger, for the first time in your life, and it broke the genetic lock. You changed. You realised your inheritance. After all these years, you knew who you were."

He nodded towards Agatha, who was still holding the necklace.

"Oh, and then it all kicks off, because this isn't just a jewel. It's a Vespiform telepathic recorder. It's part of you, your brain, your very essence. And when you activated, so did the Firestone. It beamed your full identity directly into your mind. And, at the same time, it absorbed the works of Agatha Christie directly from Lady Eddison. It all became part of you. The mechanics of those novels formed a template in your brain. You've killed, in this pattern, because that's what you think the world is. It turns out, we are in the middle of a murder mystery. One of yours, Dame Agatha."

She frowned. "Dame?"

He suppressed a wince. "Oh. Sorry, not yet."

Peering up from the now empty bowl, Donna pointed to the man.

"So he killed them, yes? Definitely?"

"Yes."

He scoffed, getting to his feet. "Well, this has certainly been a most entertaining evening. Really, you can't believe any of this surely, Lady Edizzon."

They all heard the change. A gleam appeared in the Doctor's eyes.

"Lady who?"

"Lady Edizzzzon."

"Little bit of buzzing there, Vicar."

"Don't make me angry."

"Why? What happens then?"

"Damn it, you humanzz, worshipping your tribal sky godzz. I am so much more. That night, the universe exploded in my mind. I wanted to take what wazz mine. And you, Agatha Christie, with your railway station bookstall romancezz, what'z to stop me killing you?"

Lady Eddison started to move towards him.

"Oh, my dear God. My child."

"What'zz to stop me killing you all?"

He convulsed on the spot, trembling as a sickly purple light engulfed him - and from within the cloud of colour and smoke, the wasp appeared, buzzing furiously.

"Forgive me."

The Colonel took her by the arms.

"No, no, Clemency, come back. Keep away. Keep away, my darling."

Agatha held the Firestone aloft.

"No. No more murder. If my imagination made you kill, then my imagination will find a way to stop you, foul creature."

And she ran from the room, followed closely by the Doctor, Donna and Eris. And of course, the Vespiform.

By the time they had reached the main doors, Agatha was behind the wheel of a car, tooting the horn regularly to attract the creature's attention.

"Over here! Come and get me, Reverend."

The Doctor gawped at her. "Agatha, what are you doing?"

"If I started this, Doctor, then I must stop it."

She drove away. The wasp waited for a second, choosing between the two groups of prey, then decided the Firestone was the priority. It moved to follow her, and the three of them darted towards the other car.

"Come on."

Eris got behind the wheel, and they shot off after the others.

Donna had to shout to be heard over the wind.

"Doctor. You said this is the night Agatha Christie loses her memory."

He shouted back. "Time is in flux, Donna. For all we know, this is the night Agatha Christie loses her life and history gets changed."

"But where's she going?"

They had lost sight of her a few moments previously, but soon came across a signpost for the 'Silent Pool'.

Eris swore.

"The lake. She's heading for the lake. What's she doing?"

By the time they had pulled up, Agatha was already standing at the water's edge.

"Here I am, the honey in the trap. Come to me, Vespiform."

They watched as the wasp hovered before her, and Donna realised something.

"She's controlling it."

"Its mind is based on her thought processes. They're linked."

Agatha nodded. "Quite so, Doctor. If I die, then this creature might die with me."

The three of them approached cautiously.

"Don't hurt her. You're not meant to be like this. You've got the wrong template in your mind."

As the buzz became more threatening, Donna made a decision.

"It's not listening to you."
And she snatched the Firestone from Agatha's grasp, throwing it into the lake with all her might. The wasp shot after it, vanishing below the surface.

"How do you kill a wasp? Drown it, just like his father."

The Doctor shot her a look. "Donna, that thing couldn't help itself."

"Neither could I."

The four of them stood there, watching as the water bubbled purple. Agatha sighed.

"Death comes as the end, and justice is served."

"Murder at the Vicar's Rage." He glanced down at the others, but they shook their heads. "Alright. Needs a bit of work."

"Just one mystery left, Doctor. Who exactly are you?"

Before he could come up with an answer, she doubled over in pain, sinking to the ground. Eris caught her, staring out at the lake in horror.

"Oh, it's the Firestone. It's part of the Vespiform's mind. It's dying and it's connected to Agatha."

They watched as the woman's torso glowed purple, glowing brighter and brighter before fading entirely. The light in the water was gone too, and the Doctor moved to check her pulse.

"He let her go. Right at the end, the Vespiform chose to save someone's life."

Donna put a hand to Agatha's forehead. "Is she all right, though?"

"Of course. The amnesia. Wiped her mind of everything that happened. The wasp, the murders."

"And us. She'll forget about us."

"Yeah, but we've solved another riddle. The mystery of Agatha Christie. And tomorrow morning, her car gets found by the side of a lake. A few days later, she turns up in a hotel at Harrogate with no idea of what just happened."

In fact, it turned out that Agatha Christie had turned up at a hotel in Harrogate via a trip in the Tardis. She'd been unconscious the entire time, so she herself would never know how it had happened, but there would always be a little group that would. They watched as she stood on the pathway for a moment, looking dazed, before shaking herself off and walking inside. Donna sighed.

"Lady Eddison, the Colonel, and all the staff. What about them?"

He shrugged. "Shameful story. They'd never talk of it. Too British. While the Unicorn does a bunk back to London town. She can never even say she was there."

Eris grinned. "Besides, who would ever believe that the Unicorn was a pretty girl named Constance from Bethnal Green?"

Donna raised an eyebrow at her.

"Constance?"

"Yeah."

"And how did you find that out?" She had a feeling she knew anyway, and the blush that crept up her friend's face acted as proof.

"Asking nicely, of course. How else?"

She decided to change the subject. "What happens to Agatha?"

Shooting a fond look at his daughter, he smiled. "Oh, great life. Met another man, married again. Saw the world. Wrote and wrote and wrote."

"She never thought her books were any good, though. And she must have spent all those years wondering."

Eris pulled a face, thinking. "Hang on, haven't you got something of hers in storage somewhere?"

He clicked his fingers. "Oh, yes! Come on!"

He darted back inside, followed by the others. They watched as he pulled one of the floor panels up and ducked into the space below, rooting through a jumble of random items until he retrieved a wooden chest.

"The thing is, I don't think she ever quite forgot. Great mind like that, some of the details kept bleeding through. All the stuff her imagination could use. Like, Miss Marple."

Donna tutted theatrically. "I should have made her sign a contract."

"Here we go. C. That is C for Cybermen, C for Carrionites-" he chucked the little green globe up at Eris, who pulled a face at it before setting it down again. "-and C for Christie, Agatha. Look at that."

He held up a paperback copy of Death in the Clouds with it's striking cover. A small biplane, thinly veiled by cloud, swerving to avoid a colossal wasp.

"She did remember!"

"Somewhere in the back of her mind, it all lingered. And that's not all. Look at the copyright page."

"Facsimile edition, published in the year…" The others watched with wide grins as her eyes popped out of her face. "five billion!"

"People never stop reading them. She is the best selling novelist of all time."

"But she never knew."

Eris shrugged. "Well, no one knows how they're going to be remembered. All we can do is hope for the best. Maybe that's what kept her writing."

Putting an arm around her, the Doctor smiled hopefully.

"Same thing keeps us travelling, doesn't it?"

"Oh, definitely."

His grin widened. They were finally alright again, after all the arguing and dramatics. Things were back the way they should be.

"Onwards?"

Donna nodded, squeezing them both hard enough to make them laugh.

"Onwards."

So on they went.

See you soon, and happy reading!
Much love,

Azzie xx