"Watch it Ron!" Lia snapped. "You just stamped your fat foot on my shoe. Again!"

"Well I'm sorry!" he said sarcastically. "It's not my fault, I can't see you. So unless you have some special charm for night vision or you want to stop being invisible, I suggest you to just put up with it."

"You should know, Ronald, that if I could actually see you right now, your face would be sporting a nice beautiful new bruise."

"Oh really huh? I remember what you said last week. What was it again? Oh yeah. 'I'd slap you but I don't want to make your face look any better'. What happened to that?"

"Maybe I'm feeling kind today. Mayb-"

"Will. You. Two. Shut. It." Harry hissed. "In case it escaped your notice, we're risking our lives right now! So unless you two are looking to die … shut your traps."

Ron murmured an apology, whilst Lia snickered. "Always so dramatic," she said. "I didn't realise it was possible to die from talking, my dear darling brother. Look, there's the door." She swore suddenly.

"It's open."

"Snape must already be past Fluffy," Harry cursed too.

The sight of the half ajar door seemed to fill all four of them with dread. Their bickering moments beforehand seemed childish now, as the reality of what they might be facing crashed down.

"Look. If you want to go back. I don't blame you. You can have my cloak. Or you can do your invisibility spell, Lia. It's too dangerous"

"I'm sorry Harry," Lia said. "I don't think I got that. Ron, you'll have to translate. I don't speak idiot."

"Lia," Hermione said slowly. It sounded like she was warning her.

"What, Hermy? Notice how I didn't mention you? I think you're pretty smart. And pretty too," Lia smiled.

"Lia."

She sighed. "Okay. Okay. I'm sorry. For real this time. I know this is serious. I'm just petrified so I'm trying to cover it up like this." It was one of her rare moments of honesty. She saw that Harry was opening his mouth. "And no Harry. I'm not going back just because I'm scared. I'd hate to think of what would happen to you lot without me. Besides. I'm kind of curious to see Voldemort. I wonder if he's as ugly as they say?"

"Maybe you can talk the dark lord to death," Harry said. He pushed open the door. "Your voice is maddening enough."

"What's that? There, at it's feet!" Hermione whispered.

"It's a harp. Snape must have left it there."

Lia scoffed, "As if Snape can play the harp." She had a mental image of him dressed in Greek toga, a crown of leaves resting on his oily hair, a glass of wine in one hand, as he delicately plucked the instrument with the other.

Harry ignored her. "That dog must wake up when you stop playing." He pulled out Hagrid's flute and blew a soft tune. Immediately, Fluffy's head slumped back, the growls it had previously been emitting ceased, and its eyes fell back into their lids.

"Keep playing," Ron urged.

"What musical talent!" exclaimed Lia. Harry scowled.

"I think we can get the door open. Want to go first?" Ron asked, pointing to Hermione.

"No!" Hermione replied, "What happened to chivalry?"

"Chivalry is dead," said Lia seriously.

"Ladies first," said Ron.

"Alright, alright. I'll go." Lia moved closer to the trapdoor and sat on the edge, ready to swing herself down.

"Wait!" said Harry. "I should go first."

"Pffft. No! Go away! This is my moment of honour." She stuck out her tongue. "Don't you know that I'm only honourable when you're around? And don't be such a Gryffindor. You're not that brave."

"I'm your brother. Your older brother."

Lia paused. "How do you know you're older?"

"Hagrid told me."

"No, he didn't."

"Yes, he did."

"No he di-"

"Alright he didn't. I lied." He stopped, searching for words. "But I'm more mature. And Lia," His expression was promptly sombre, "I could never live with myself if something happened to you."

Lia's eyes softened. "Aw. That was just like a quote out of a movie. Come on. Since when did you worry about me? It's always been the other way round. And actually … why are you worrying in fact? Let's be real. I'm better at magic. If whatever done there is dangerous, I'll probably be more equipped to handle it than you."

Harry swallowed. "At least you got that right. If Snape can do it. You can too, Lia."

Lia sighed. "I told you. It's. Not. Snape … If I die, tell Pansy and Malfoy that I hate them, okay? And tell Tracey that she was an average friend." With that, she gave a small shove and let herself fall into the hole.

She closed her eyes, bracing herself to drop into the mouth of a giant sea monster and get crushed by its sharp elongated incisors. When nothing happened, she dared to peek open one eye.

"LIA!" Harry yelled. "What's happening…? Where are you? Hello? Lia…? What's going on? LIA! HELLO? ANSWER ME GODDAMNIT!"

"It's okay! It's okay. You can come down."

Harry went first, then Ron, and finally Hermione, who was still playing a low note on the flute, even as she fell through the trapdoor. Lia raised an eyebrow at her.

"Can't be too careful," she said.

It was then that Lia finally chose to look down. She gasped. Oh dear. She really should have made sure that she was more aware of her surroundings, before she had urged the others to jump too.

"Um, guys?" she whispered.

"Lucky this plant thing's here, really," Ron said.

Lia would have laughed, had she not been terrified.

"Lucky? Lucky!" screamed Hermione. "Look at us!" Ron and Harry looked down and their eyes widened as they saw that their legs had been enwrapped by thick tendrils. "Honestly Ron, were you born this stupid or did you take lessons?"

"Damn, Hermione," Lia whistled. "I'm impressed." But she couldn't be too impressed, since she realised that the tendrils were quickly moving up her hips, soon latching onto her waist. "Ah!" she yelled. "Hermione. I think we studied this in herbology once. This is … god what was it called? The one that wraps tighter when you move?"

Her friend clapped a hand to her mouth. "Oh! I know! It's Devil's Snare."

"Oh, woah, just great. It's so helpful knowing the name of the plant. WHEN I'M ABOUT TO DIE!" Ron was cussing again.

"Ron!" Lia yelled. "Harry!"

"Stop moving," ordered Hermione. "And shut up Ron. I'm trying to think."

"HOW CAN I STOP MOVING!" He was panicking. "I'm going to be squeezed to death!" He swore. "I bet Fred and George are going to have a right laugh about this. Hugged to death by a plant!"

"I can't breathe," Harry gasped.

"Hermione," Lia said slowly. "Hurry the heck up."

"Ohhh …. Ohhhhh … Merlin. What did Professor Sprout say? What was it? Oh ... I can't think! What was it? ... Devil's Snare likes the dark and the damp."

"Light a fire then!" Harry managed to choke out.

"Yes, yes, that's right … but how … how?" Hermione cried. "THERE'S NO MATCH!" She looked close to tears.

"ARE YOU MAD?" Ron roared. "ARE YOU A WITCH?"

It was at precisely that second, that Lia had finally relaxed her body enough, so that she was able to wriggle slightly out of the Devil's Snare's firm grasp, and gain enough mobility so that she could at least grab out her wand and point it at the plant.

"Incendio," she chanted. A streak of fire whipped out from the end of her wand. It was only seconds before the plant had hid itself from the light and moved far away enough that they were able to shake the remaining tendrils off their bodies, and finally pull free from its grasp.

Lia swore loudly. "Never again."

"Good thing you pay attention in Herbology, Hermione." Harry said. "And good that you know your spells, Lia."

"Yeah," Ron snorted. "And lucky that most of us don't lose our heads in a crisis – there's no match, honestly, can't even…"

Lia laughed. "You weren't exactly much better, Ron. How. Can. I. Stop. Moving," she grunted the words out, as if she were a caveman. "Hugged to death by a plant!" she then said in a feminine tone. She pretended to faint and proceeded to double over laughing.

"This way," Harry said. He pointed down a passageway, carved out of stone. It looked to be the only way forward.

As they walked, Lia listened carefully. There was definitely water dripping down the walls. Were they under the Great Lake then? But the Slytherin common room was partly under that lake too wasn't it? How funny would it be if her roommates were just bricks away from her? She then imagined that Malfoy was there, and she could quickly think of a perfect jinx for him.

"Oi. Can you hear me?" she almost murmured.

"Do you hear something?" Ron whispered. Lia blanched. She hadn't said that thought out loud had she? But no, as she strained her ears to listen, there was a rustling sound, it was faintly like wind rustling through a thin curtain, or even … wings beating, if she wasn't wrong. As the four entered the room, they were surrounded by an array of strange-looking, glittering birds that soared around chaotically.

Lia stared entranced at the birds, while the other three struggled with the door. It didn't look like the old, heavy thing was going to open.

"Guys!" She'd had a sudden realisation, "Don't waste your efforts. That door's not going to move. Not until we find the key at least. Come here! Look! They're not birds. They're keys!"

"We're looking for a big, old-fashioned one – probably silver, like the handle is," said Ron, flicking his eyes between the keys and the door.

"Ron!" Lia faked awe. "Keep talking, someday you might just say something intelligent!" Then she pulled out her wand. "Accio old key."

At least half of the keys changed direction and zoomed at her. Although they'd looked rusty before, now, they all had sharp edges. The keys looked ready to impale her.

"Protego!" Lia barely had time to draw up the shield charm as they grew nearer. As the keys touched the protective barrier, they bounced off, harmless, and flew about aimlessly once more.

"You were saying?" smirked Ron.

"Shut up," said Lia. "Maybe if I try 'oldest key'?"

She didn't have to worry about getting almost killed by flying inanimate objects again. At least in the confusion of the keys all soaring out at Lia, Harry had had time to grab the large silver one with the roughly bent wing, as he chased after it on the broomstick. He put the struggling thing into the lock, and thankfully, it clicked and the door swung open.

"Chess," Lia groaned. "Oh, it's chess."

"I think," Ron said. "We have to be chessmen. Now don't be offended, I'm not being rude. But none of you are really that great at chess b-"

"And the idiot is back," Lia said, "Please, instruct me, your stupidness."

"We're not offended," Harry replied rapidly. "Tell us what we need to do."

"Alright, Lia you need to go and stand beside that bishop. Harry you go to the other bishop. Yes, that one on the other side. And Hermione, you go next to him as that castle."

"What about you?"

"I think I'll be a knight."

Apparently the chess pieces had ears and could somehow listen, for those four exact pieces that Ron had pointed to, moved off of the board, so that they could now replace them. Lia waited patiently as Ron directed the black pieces. It was an intense game - every time a spot was lost; the opposing side would smash the taken piece to smithereens.

Ron then continued to have the 'marvellous' idea of sacrificing himself. Everyone was taking it really well.

"Ron. Don't be daft. You can't," said Lia. "That's the dumbest idea I've heard yet. You can't sacrifice yourself."

Lia wondered what would have happened if everyone here was a Slytherin. Maybe they could have put McGonagall under the imperius curse. But she didn't think anyone in first year could do that spell yet. Even she couldn't. But then, many of them did have older siblings. Or they could always ask Montague. Or Flint. Those boys probably already knew the cruciatus curse, let alone 'Imperio'.

"It's chess. You have to make sacrifices." Ron pointed to the board. "If the queen takes me. Then you'll have a clear path to checkmate the king, Harry."

"Ron-"

"You have to hurry up. He could already have the stone."

Lia met Harry's eyes. She shook her head. She couldn't think of any other alternative.

"Ready?" Ron asked. He looked pale, but his expression was resolute. Lia felt bad for teasing him so much. "I'm going now. You all have to keep moving once this round's over. Go through the door."

She watched in horror as Ron was stuck on the head. He looked as if he had been knocked out. Lia hoped that he didn't have a concussion … or worse. Harry moved one last time. And the game was over. They'd won.

"What if he's-" Hermione whispered as they ran through the passage.

"He's alright," Harry said, trying to at least sound convincing to himself.

The room they entered next was filled with a putrid stench. Lia gagged. There was a troll collapsed on the ground in front of them, a large bump on the creature's head. She let out a slow whistle. "Thank god we didn't have to fight that one."

The three of them moved forward and they were faced with a table: on it lay a variety of bottles of differing shapes, sizes and smells. Over the threshold, two fires suddenly lit up. One for each opposite doorway. Black flames for the doorway leading forward, purple flames for the one leading back.

"We're trapped," Lia looked around.

"This must be Snape's creation," Harry said.

She pulled out a roll of paper that had been lying next to some bottles, and opened it, holding it in her hands so that they could all read though it.

"Danger lies before you, while safety lies behind,

Two of us will help you, which ever you would find,

One among us seven will let you move ahead,

Another will transport the drinker back instead,

Two among our number hold only nettle wine,

Three of us are killers, waiting bidden in line.

Choose, unless you wish to stay here forevermore,

To help you in your choice, we give you these clues four:

First, however slyly the poison tries to hide

You will always find some on nettle wine's left side;

Second, different are those who stand at either end,

But if you would move onward, neither is your friend;

Third, as you see clearly, all are different size,

Neither dwarf nor giant holds death in their insides;

Fourth, the second left and the second on the right

Are twins once you taste them, though different at first sight."

"It's logic. It's a puzzle," Hermione said. She looked fascinated, happy even.

Lia nodded her head. "It's a shame how few great wizards have logic these days. They'd be stuck here forever."

"We're not going to be stuck here forever too … are we?" Harry asked cautiously.

She scoffed. "What do you take us for? You should be thankful that your friends are both logical." Lia paused. "And great. Read here. Out of these seven bottles. There's two that are wine. Three that are poisoned. One will take us backwards through the purple fire. So back to safety. Back to Ron. Then the last one of them will get us forward though the black flame." She swallowed. "To danger."

"How do we know which one to drink?" Harry demanded.

Hermione and Lia read the paper together multiple times. She thought that she could almost memorise it in her mind. They muttered and discussed together until Hermione finally pulled one out. A small bottle. The smallest bottle.

"This one will get us though the black fire. It'll take you towards the stone," Lia said.

Harry glanced at it. It was a tiny, tiny bottle.

"It's only enough for one person," Harry said. "It's hardly even enough for a swallow."

The three of them looked at each other.

"Which one for the purple flames?" he asked.

Hermione pointed to a round bottle that sat at the right end of the line. Again it was a small bottle. A slight fraction bigger than the one Harry was holding. But small, all the same.

"One of us will have to stay here," Hermione said.

Lia looked at them. "I volunteer," she said. "I volunteer as tribute."

"What?"

"Haven't you watched that movie?"

"This isn't the time!"

"Look guys don't stress. It's going to be alright. Hermione will go through the purple flames, get back to Ron, grab the brooms from the key room and jet off to find Dumbledore. Harry, I know you'll argue with me otherwise, you go through the black flames." She gulped. "Try not to die, will you? And me? I'm going to try to duplicate that potion after you drink it, Harry. I'll join you as soon as I can."

Harry looked a bit shocked. "Usually you'd be the one insisting to go though. To go meet Voldemort."

"I know," she sighed. "I'll have to let you have the privilege first. Give him hell won't you? For killing mum. And dad. And like one thousand other people. I know you Harry, and if I left you here you'd probably poison yourself, or burn to death in your haste to get through the flames."

Harry grinned then, "I'll miss you Lia. And you Hermione. Tell the Dursleys that were the worst adoptive family ever if I die."

"You're not going to die," Lia said.

Hermione's lip trembled and she threw her arms out as she hugged them both.

Lia rolled her eyes at her brother. "And you stole my line."

"Harry, Lia, you're both great wizards, you know," Hermione said

Lia and Harry flushed and they both simultaneously replied, "Not as good as you."

"Me!" said Hermione. "Books! And cleverness! There are more important things - friendship and bravery and - oh Lia, oh Harry - be careful!"

"I'm always careful," said Lia. "Not sure about the other Potter though."

"You drink first," Harry said.

Hermione drank from the round bottle immediately shivered.

"Poison?"

"No, no, it just … tastes like ice."

"Well, go. Now! Quickly, before it wears off."

"Good luck. Be careful," Hermione disappeared into the flames.

"Harry," Lia said. She was horrified to find her eyes watering. "Harry, listen to me. I don't care what Voldemort says. What he threatens to do. Don't be noble today okay? Save yourself. Grab the stone and just get out. As fast as you can. I'll meet you there. As fast as I can. I promise."

Harry bit his lip, he looked awkward, and Lia almost laughed at the sight of him.

Ever since he'd been a preschooler he'd never known what to do when girls cried. And now that his sister was crying? His sister, who didn't even shed a tear when her pet rabbit died? Harry looked mortified.

"I love you, Lia," he finally said. He drank all of the tiny bottle up in one go, and disappeared into the black flames.

"Love you too, Harry." A thought lingered in the back of her mind.

"Harry! Harry! HARRY!" She yelled. But it was no use. Her brother had already stepped away past the flames, into the darkness that waited.

"It's Quirrell," Lia said to no one at all. "It has to be. Oh, how could I have forgotten to tell him? Harry must be in for a nasty surprise."

She flung herself at the potions table, and grasped at the empty vial that he had left.

She could spot a tiny droplet of liquid left over in the bottom of the glass. She knew that it wouldn't be enough to protect her. She just needed a way. A way to multiple the potion.

Of course! A doubling charm!

She started working on it right away.