SuperPotterLock - The Half-Blood Prince

by Nurmengardx

One morning, as they were lounging around on the patio, two handsome tawny owls landed in front of them. 'These are school owls,' Cas said, his eyes widening. 'These must be our exam results.' Both the owls lifted their legs, and Cas and Dean took the letters from them. 'Accio glasses,' said Dean, Summoning the glasses Cas had charmed for him. 'Okay, you first,' he said eagerly.

5. The Half-Blood Prince

The Half-Blood Prince

Dean hurried down to the silver swan portrait, passing by John who was half asleep twitching on the sofa, and found Cas waiting for him.

Cas gave him a quick kiss, then they walked together to the hospital wing.

'Ah, Castiel, I was hoping you would come and see me soon,' Madam Pomfrey said when she saw them come through the door. 'And it's good to see you too, Dean.'

'Did you have a good summer, Madam Pomfrey?' Cas asked, smiling at her.

'I did,' she said brightly, 'but I know you don't have a lot of time this morning, so we'll save the chit chat. Here, I have something for you.' She bustled off to her office and returned with a polished wooden box. She held it out and looked almost nervous. 'I have an offer. I haven't done this in a while, but I got Dumbledore's permission, so…' She opened the box, revealing a white tie with blue stripes, and a white badge with the letter 'H' on it. 'I was wondering if you would like to be my apprentice?'

Cas gaped at her.

'If you accept, you'll need to spend at least two nights a week here, and one weekend a month. Of course, we would work around your Quidditch practice if you still wanted to play, and Hogsmeade weekends. You'll be very busy with school work, so I would recommend you drop one of your subjects, but it's up to you.'

Cas didn't say a word, completely dumbfounded, until Dean gently elbowed him.

'Cas,' he said with a grin. 'Say something.'

It took Cas another moment, but then he tore off his Ravenclaw tie, throwing it into Dean's chest, then hastily tied on his new one. 'I'll drop Ancient Runes.' He beamed as he pinned his new badge right next to his prefect badge, and a faint glow filled the air around him.

Madam Pomfrey smiled too. 'Would you like to see your new room before you go to breakfast?'

'I get a room?' Cas said, astonished.

'Absolutely.' She led them through the hospital wing towards her office. 'You'll be learning all about running the ward this year, and maybe next year we can get you some time at St Mungo's, what do you think?' she said as she walked.

'That would be incredible.'

They approached Madam Pomfrey's office, and she opened a door opposite hers.

Inside was a small, plain room, with a desk, a bright window, and a comfortable bed.

'This is for the evenings you work here, but you're welcome to use it any time you like.'

'This is… I've never had my own room.'

'I thought you might like the peace and quiet.'

Cas nodded. 'Will there be an exam?'

'No, you'll just have regular assessments done by myself. I don't foresee you having any problems with them, but you'll have plenty of notice.'

'That sounds good.'

Madam Pomfrey smiled again. 'Go on, now, get some breakfast before your first lesson.'

'Yes, Ma'am.'

Cas squeezed Dean's hand all the way back through the hospital wing.

'Cas!' Dean exclaimed as soon as they'd closed the door. 'This is amazing!'

Cas put his hands on his head, hardly able to contain himself. 'I can't believe it!'

'You're gonna be a Healer!'

'Apprentice Healer,' Cas corrected. 'But yes!' He wrapped his arms around Dean, trembling with excitement.

Dean laughed. 'Come on, we gotta get something to eat.'

They made it to breakfast in time to grab some bacon and toast, and sit themselves down at the Gryffindor table.

John and Sherlock were there, but John was pale and still twitching, and chewing unenthusiastically on a cold slice of toast.

Hermione noticed Cas's new tie immediately, and he explained to them what Madam Pomfrey had set up for him.

'That's amazing, Cas!' Hermione exclaimed.

'Yeah, with the amount of trouble we get into, it'll be good to have a proper Healer around,' said Harry.

After they had eaten, they remained in their places, awaiting their Heads of Houses descent from the staff table. The distribution of timetables was more complicated than usual this year, for they first needed to confirm that everybody had achieved the necessary O.W.L grades to continue with their chosen N.E. .

Hermione was immediately cleared to continue with Charms, Defence Against the Dark Arts, Transfiguration, Herbology, Arithmancy, Ancient Runes, and Potions, and shot off to first-period Ancient Runes class without further ado.

Dean proudly produced his results when it was his turn, and Professor McGonagall gave him a rare smile, clearing him for his choices.

Cas told Professor Flitwick of his decision to drop Ancient Runes, but he too was cleared for the rest of his choices.

Professor McGonagall turned to Parvati Patil, whose first question was whether Firenze the centaur was still teaching Divination.

'He and Professor Trelawney are dividing classes between them this year,' said Professor McGonagall. 'The sixth year is being taken by Professor Trelawney.'

Parvati looked disappointed, but she and Lavender set off for the North Tower.

John got up to follow them once his classes had been approved. After Umbridge had made him take his O. without Colin to transcribe for him, he'd gotten mostly high grades, though he didn't feel as though he'd earned them.

'You really don't need to take Divination,' Sherlock said with a frown.

'How many times are we going to have this conversation?' John snapped. 'I'll take Divination if I want to.' He shoved on his bag and stormed from the Great Hall. As he reached the door, however, he felt Sherlock's hurt across their link and sighed.

I'm sorry, he whispered in Sherlock's mind. Enjoy your free period.

It was enough, and he felt Sherlock relax, soothed.

It was odd, climbing up to the Divination classroom alone. He usually had Ron and Harry to listen to, but it was quiet without them.

When he arrived, it was obvious how few people had chosen to continue the subject. Among the Gryffindors, John, Parvati, Lavender Brown, Seamus and Dean Thomas were the only ones, and John suspected that Seamus and Dean were only there for an easy grade.

There were no Ravenclaws or Slytherins, but to John's surprise, he saw Molly Hooper sitting at a table. He approached her and smiled.

'I didn't know you took Divination,' he said, sitting next to her.

Molly shrugged. 'Apparently I was good enough to keep taking it.'

Now that he was inside the room, the usual strong incense in the room soothed John's mind. His almost perpetual headache all but vanished, and his muscles unclenched as the warmth from the fire that always burned in the fireplace washed over him. The room wavered as his body tried to fall asleep, all of a sudden relaxed enough to do so, but he yanked himself out of his sleep deprivation.

'How was your summer?' Molly asked.

Professor Trelawney had not yet entered the room, so they were all chatting quietly.

John shrugged. 'Not great,' he murmured, his visions fluttering around him. Less insistent in the classroom, but still there.

Molly gave him a sympathetic look.

'Nevermind,' John said grimly. 'How was yours?'

Molly smiled and blushed. 'I - um - I got a boyfriend.'

John's eyebrows shot up. 'Really? That's lovely, Molly. Good for you.'

'Yeah, he's really nice.'

'I'm happy for you.'

Just then, Professor Trelawney finally arrived, and began passing around glass jars with flickering flames inside, informing them that they would be practising pyromancy.

John smiled, remembering all the times they'd spent huddled around the little flames the Hermione would conjure when it was cold. He rested his head on his hand, propped up by his elbow, and let his eyes unfocus. He had never been good with fire omens, but he approached it in the same way he would the crystal ball. Like cloud watching. Nothing happened at first, but then the flames twisted and flickered into shapes he recognised. He saw Sherlock's curly hair and smiled, but then, before he could react, he was plunged into a vision, feeling as though he had been slapped in the face.

His ears rang, and it took a moment to adjust to the sudden darkness. It was night, and everything had a tinge of sickly green to it. Then a figure moved and he realised with a jolt that it was Sherlock. He was running, aiming his wand over his shoulder as he went up a spiral staircase. John couldn't tell which staircase it was, but he knew it was Hogwarts. Sherlock looked scared, which always frightened John. It took a lot to scare Sherlock.

John watched him throw himself at a door, breaking through it and sprinting out onto a large balcony, and John finally recognised it as the West Tower.

Sherlock raced to the edge, stopping with his hands on the short parapet. He looked over his shoulder again, his face bathed in green light.

John's chest tightened. He followed Sherlock's gaze, but he could not see what Sherlock was running from.

Sherlock's hair fluttered in the wind as he turned back to the stone parapet. His eyes raked the darkness below, and his mouth tightened into a grim frown. Then, he stepped up onto the stone wall.

'No!' John shouted, but there was nothing he could do. He could only watch as Sherlock took a deep breath and plunged into the darkness.

John snapped back to the Divination classroom, his throat sore from the volume of his scream, and everyone was staring at him.

Molly rubbed his back but he flinched away from her, her touch overwhelming his senses as he struggled to regain control of himself.

He felt Sherlock's alarm, but pushed him away, seeing him fall over and over in his head. He got to his feet, trembling.

'I have to go,' he mumbled, stumbling towards the trapdoor and down the ladder, ignoring Professor Trelawney's protests.

Once outside of her classroom, the incense and perfume dissipated, and his headache returned. He carried on walking, struggling to catch his breath, not paying attention to where he was going until Sherlock caught hold of him along a deserted corridor.

John burst into panicked tears, wrapping his arms around Sherlock's waist.

'What did you see?' Sherlock murmured.

But John shook his head. He couldn't bring himself to give it voice. It didn't matter though. Now he had seen it, it would come true, he knew that much. And as with Sirius, there would be nothing he could do to save Sherlock. He bunched his fists in Sherlock's robes and hastily pushed Sherlock away when he felt him gently trying to pull the vision from his mind.

'Don't,' John said, his voice muffled. 'I don't want you to see it.'

Sherlock's curiosity only intensified, but he did as he was asked and left it alone.

There wasn't long left before they had to go down to Defence Against the Dark Arts, so they sat together right there in the hallway, in the warm sunlight streaming through the windows.

John was still shaking by the time they had to go, and more than a little nauseous, but he could breathe and he could walk, so that would just have to do.

They arrived just as the classroom door opened and Snape stepped into the corridor, his sallow face framed as ever by two curtains of greasy black hair.

'Inside,' he said.

John held Sherlock's hand and joined the back of the queue. It was a relief to be able to have Sherlock in most of his classes this year.

Snape had already imposed his personality upon the room; it was gloomier than usual as curtains had been drawn over the windows and it was lit by candlelight. New pictures adorned the walls, many of them showing people who appeared to be in pain, sporting grisly injuries or strangely contorted. Nobody spoke as they settled down, looking around at the shadowy, gruesome pictures.

Cas and Dean sat down together, both looking deeply uncomfortable at the sight of the pictures, and the blood drained from Cas's face, his eyes darting back towards the door.

'I have not asked you to take out your books,' said Snape, closing the door and moving to face the class from behind his desk; Hermione hastily dropped her copy of Confronting the Faceless back into her bag and stowed it under her desk. 'I wish to speak to you and I want your fullest attention.'

His black eyes roved over their upturned faces.

'You have had five teachers in this subject so far, I believe. Naturally, these teachers will all have had their own methods and priorities. Given this confusion I am surprised so many of you scraped an O.W.L in this subject. I shall be even more surprised if all of you manage to keep up with the N.E.W.T work, which will be much more advanced.'

Snape then set off around the edge of the room, speaking now in a lower voice.

'The Dark Arts,' said Snape, 'are many, varied, ever-changing and eternal. Fighting them is like fighting a many-headed monster, which, each time a neck is severed, sprouts a head even fiercer and cleverer than before. You are fighting that which is unfixed, mutating, indestructible.

'Your defences,' Snape continued, a little louder, 'must therefore be as flexible and inventive as the Arts you seek to undo. These pictures,' he indicated a few of them as he swept past, 'give a fair representation of what happens to those who suffer, for instance, the Cruciatus Curse,' he waved a hand towards a witch who was clearly shrieking in pain, and John flinched as screams and pain pressed against him, 'feel the Dementor's kiss,' at a wizard lying huddled and blank-eyed slumped against a wall, 'or provoke the aggression of the Inferius,' to a bloody mass upon the ground.'

Dean gagged and clamped a hand over his mouth, but Snape thankfully didn't appear to notice. Cas put a gentle hand on his knee, and felt the warmth from his fingers spread through his body, soothing his roiling stomach.

'Has and Inferius been seen, then?' said Parvati in a high-pitched voice. 'Is it definite, is he using them?'

'The Dark Lord has used Inferi in the past,' said Snape, 'which means you would be well-advised to assume he might use them again. Now…'

He set off again around the other side of the classroom towards his desk, and again, the class watched him as he walked, his dark robes billowing behind him.

'... you are, I believe, complete novices in the use of non-verbal spells. What is the advantage of a non-verbal spell?'

Hermione's hand shot into the air. Snape took his time looking around at everyone else, making sure he had no choice, before saying curtly, 'Very well - Miss Granger?'

'Your adversary has no warning about what sort of magic you're about to perform,' said Hermione, 'which gives you a split-second advantage.'

'An answer copied almost word for word from The Standard Book of Spells, Grade 6,' Snape said dismissively, 'but correct in essentials. Yes, those who progress to using magic without shouting incantations gain an element of surprise in their spell-casting. Not all wizards can do this, of course, it is a question of concentration and mind power which some… lack.'

Cas allowed himself a small smile. Though not always intentionally, he'd been able to use spells non-verbally for years now, ever since he'd set Malfoy's newspaper on fire two years previously.

'You will now divide,' Snape went on, 'into pairs. One partner will attempt to jinx the other without speaking. The other will attempt to repel the jinx in equal silence. Carry on.'

Sherlock and John partnered up, but John made no attempt to cast a spell, or a Shield Charm. He was barely strong enough to cast one normally; there was no chance he'd be able to do it non-verbally. Sherlock cast his gaze about and attempted to jinx several of the Slytherins instead. After a few tries, he managed to catch Malfoy in the back of the head with a Leg-Locker Curse, and smirked as his legs sprung together and he crashed to the ground. As their spells were non-verbal, no one could tell where it had come from, and Malfoy turned back to Goyle, flushed and embarrassed.

Dean and Cas were paired together and stood a little apart from the rest of the class.

'You good?' Dean whispered to Cas.

Cas nodded and smiled. Dean was one of the few people he trusted to throw jinxes at him, and almost nothing could break his Shield Charm.

Dean took a deep breath and set about trying to cast a spell without a word, but he got frustrated after a few minutes.

'It's all right,' Cas said encouragingly, 'it's difficult, you don't have to get it right away.'

Dean nodded. He shook out his hands and steadied himself. He stared Cas right in the eye, raised his wand and a jet of red light erupted from the end of it. It bounced harmlessly off of Cas's Shield Charm, and he grinned widely.

'Well done, Dean,' Cas smiled, but then it was his turn to try to cast a jinx. 'Why don't you practise the Shield Charm a little first,' he said nervously. It was one thing throwing Dean across the room when they were in DA meetings, but doing it in front of Snape and the Slytherins was another matter, and he was worried he would get in trouble.

Dean understood, though, and silently cast his Shield Charm until Cas was satisfied with it.

Cas cast a Jelly-Legs Jinx, and it was a lot stronger than he'd hoped it would be. It shattered Dean's Shield Charm, but it was slowed down enough that it only had the jinx's intended effect of making Dean wobble on the spot, without hurting him. Cas let out a sigh of relief and removed the jinx.

'That was good,' Dean said, adopting his usual teaching voice he'd used in meetings. 'Real good.'

'Thank you. I would prefer it if you practised more on me for now. If you don't mind.'

'Sure.'

It was easier after his first Disarming Charm, and he knew that Cas's Shield Charm was strong enough to take anything he threw at it, so he worked himself up to his stronger curses, but got stuck with the Reductor Curse. No matter how much he concentrated, he couldn't seem to bring it forth. He just needed practice, he reasoned with himself, and went back to some weaker jinxes to really get the feel for it.

Ron, who was supposed to be jinxing Harry, was purple in the face, his lips tightly compressed to save himself the temptation of muttering the incantation. Harry had his wand raised, waiting to repel a jinx that seemed unlikely to ever come.

'Pathetic, Weasley,' said Snape, after a while. 'Here - let me show you - '

He turned his wand on Harry so fast that Harry reacted instinctively; all thought of non-verbal spells forgotten he yelled, 'Protego!'

His Shield Charm was so strong that Snape was knocked off balance and hit a desk. The whole class had looked around and now watched as Snape righted himself, scowling.

'Do you remember me telling you we were practising non-verbal spells, Potter?'

'Yes,' Harry said stiffly.

'Yes sir.'

'There's no need to call me "sir", Professor.'

Several people gasped, including Hermione, but Sherlock sniggered and Dean just barely turned a snort into a loud cough.

'Detention, Saturday night, my office,' said Snape. 'I do not take cheek from anyone, Potter… not even the Chosen One.'

'That was brilliant, Harry!' Ron chortled, once they were safely on their way to break a short while later.

'You really shouldn't have said it,' said Hermione, frowning at Ron. 'What made you?'

'He tried to jinx me, in case you hadn't noticed!' fumed Harry. I had enough of that during those Occlumency lessons! Why doesn't he use another guinea pig for a change? What's Dumbledore playing at, anyway, letting him teach Defence? Did you hear him talking about the Dark Arts? He loves them! All that unfixed, indestructible stuff-'

'Well,' said Hermione, 'I thought he sounded a bit like you.'

'Like me?'

'Yes, when you were telling us what it's like to face Voldemort. You said it wasn't just memorising a bunch of spells, you said it was just you and your brains and your guts - well, wasn't that what Snape was saying? That it really comes down to being brave and quick-thinking?'

Harry didn't argue any further.

'Harry! John!'

They looked around, Andrew Kirke, one of the Beaters on the previous year's Gryffindor Quidditch team, was hurrying towards them holding a roll of parchment.

'For you,' he panted, holding it out. John let Harry take it. 'Listen, Harry, I've heard you're the new Captain. When're you holding trials?'

'I'm not sure yet,' said Harry. 'I'll let you know.'

'Oh, right. I was hoping it'd be this weekend-'

But Harry had stopped listening; he had just recognised the thin, slanting writing on the parchment, and walked away from Kirke mid-sentence.

Dear Harry and John,

I would like to start our private lessons this Saturday. Kindly come along to my office at eight p.m. I hope you are enjoying your first day back at school.

Yours sincerely,

Albus Dumbledore

P.S. I enjoy Acid Pops

John gulped. He knew that Harry would be having private lessons with Dumbledore, but he had not expected to be included. He felt a pit form in his stomach, and he knew the lessons would be painful to say the least.

'He enjoys Acid Pops?' said Ron, who had read the message over Harry's shoulder.

'The password to Dumbledore's office,' said Sherlock, his eyes flicking back and forth over the message, struggling to keep his concern from spilling over into John's mind.

'Ha! Snape's not going to be pleased,' said Harry. 'I won't be able to do his detention.'

After break, Hermione and Sherlock went off to Arithmancy, but the rest of them had a free period, so they spent the hour in the Gryffindor common room, tackling the homework Snape had given them.

Dean felt a familiar clenching in his stomach, but he adjusted his glasses on his face and briefly squeezed Cas's hand for reassurance.

They took a quick break to get something to eat for lunch, then it was time for Cas and Dean to head down to Care of Magical Creatures.

They were the first to arrive at Hagrid's cabin, and the class was extremely small. There were no Slytherins to be seen, only Anthony Goldstein from Ravenclaw, and Justin Finch-Fletchely and Susan Bones from Hufflepuff. Dean was the only Gryffindor to have continued the class as well.

Hagrid waited longer than he should have, anxiously watching the castle to see if anyone else was coming, but eventually he moved on to the lesson, looking crestfallen.

'Got somethin' special fer yeh firs' lesson,' he said, doing his best to put on a bright voice.

Dean winced, knowing full well that Hagrid's version of special was very different from most people's, but he needn't have worried.

Hagrid led them around the side of his cabin to a table that had several branches standing up on it, and resting on the branches were three small birds, each tethered to the branches with delicate silver chains. They had hot pink feathers, tipped in lime green and turquoise. One of them opened its brilliant orange beak, but no sound came out. Cas let out a soft gasp of delight.

'Anyone know wha' these are?' Hagrid asked, and Cas tentatively put his hand up. 'Go on then, Cas.'

'They're Fwoopers,' Cas said. 'Native to Africa. Where did you get these, Hagrid?'

Hagrid beamed at him. 'Exactly righ', Cas,' he said. 'These ones are borrowed from a friend o' mine, so they're not stayin', bu' I thought they'd be good ter look at fer a lesson.'

Cas glanced at them nervously.

'What?' Dean whispered at his expression.

'You need a permit for these,' Cas whispered back. 'I doubt Hagrid bothered to get one.'

'Are they normally silent, Hagrid?' asked Susan.

'Great question,' said Hagrid. 'Their song causes insanity, so they have ter have a Silencing Charm on 'em at all times.'

Cas grimaced again, knowing that Hagrid wasn't supposed to be using magic, but hoping he had anyway to make the Fwoopers safe.

They spent the lesson learning all about the Fwoopers, their natural habitat, and the effects of their song. Towards the end of the lesson, Cas noticed that they had shed a few feathers on the table.

'Hagrid, may I have these?' Cas asked, pointing at them.

''Course yeh can,' said Hagrid. Despite not having as many students turn up for class as he had hoped, he had relaxed and seemed to enjoy teaching a class that actually wanted to be there.

Cas gathered up the feathers and pocketed them. 'Usually you'd have to buy these,' he explained to Dean. 'We can make a Veritaserum antidote with them.'

'Good thinking,' said Dean, and he quickly kissed Cas's cheek.

Cas blushed. 'Dean, we're in class,' he admonished, but quickly squeezed Dean's hand.

At the end of the lesson, they helped Hagrid put the Fwoopers to sleep in cages, and departed for that afternoon's double Potions lesson. When they arrived in the corridor outside the dungeon classroom, they saw a similar story to Hagrid's class. Very few people seemed to have achieved the grade required to continue at N.E.W.T level.

Crabbe and Goyle had evidently failed, but four Slytherins had made it through, including Malfoy, along with a few Ravenclaws. Molly Hooper and Ernie Macmillan were there, as were John, Sherlock, Harry, Ron and Hermione, though John looked mildly surprised that he had been invited to continue.

Then the dungeon door opened and Slughorn waved them inside. The dungeon was, most unusually, already full of vapours and odd smells.

The Slytherins all sat at a table together, while Molly took a table with John, and Sherlock, while Cas and Dean sat together at a table on their own, nearest a gold-coloured cauldron that was emitting a seductive scent. Harry, Ron and Hermione sat at the table next to theirs, with Ernie, while the remaining Ravenclaws took their own table.

'Now then, now then, now then,' said Slughorn, whose outline was quivering through the many shivering vapours. 'Scales out, everyone, and potion kits, and don't forget your copies of Advanced Potion Making…'

'Sir?' said Harry, raising his hand.

'Harry, m'boy?'

'I haven't got a book or scales or anything - nor's Ron - we didn't realise we'd be able to do the N.E.W.T, you see-'

'Ah yes, Professor McGonagall did mention… not to worry, my dear boy, not to worry at all. You can use ingredients from the store cupboard today, and I'm sure we can lend you some scales, and we've got a small stock of old books here, they'll do until you can write to Flourish and Blotts…'

Slughorn strode over to a corner cupboard and after a moment's rummaging emerged with two very battered-looking copies of Advanced Potion Making, which he gave to Harry and Ron, along with two sets of tarnished scales.

'Now then,' said Slughorn, returning to the front of the class, 'I've prepared a few potions for you to have a look at, just out of interest, you know. These are the kind of thing you ought to be able to make after completing your N.E.W.T.s. You ought to have heard of 'em, even if you haven't made 'em yet. Anyone tell me what this one is?'

He indicated the cauldron nearest the Slytherin table that had what looked like plain water boiling inside it.

Hermione's well-practised hand hit the air before anybody else's; Slughorn pointed at her.

'It's Veritaserum, a colourless, odourless potion that forces the drinker to tell the truth,' said Hermione.

'Very good, very good!' said Slughorn happily. 'Now,' he continued, pointing at the cauldron nearest the Ravenclaw table, 'this one here is pretty well-known… featured in a few Ministry leaflets lately, too… who can-?'

Hermione's hand was fastest once more,

'It's Polyjuice Potion, sir,' she said.

Most of them, too, had recognised the slow-bubbling, mudlike substance in the second cauldron.

'Excellent, excellent! Now, this one here… yes, my dear?' said Slughorn, now looking slightly bemused as Hermione's hand punched the air again.

'It's Amortentia!'

'It is indeed. It seems almost foolish to ask,' said Slughorn, who was looking mightily impressed, 'but I assume you know what it does?'

'It's the most powerful love potion in the world!'

'Quite right! You recognised it, I suppose, by its distinctive mother-of-pearl sheen?'

'And the steam rising in characteristic spirals,' said Hermione enthusiastically, 'and it's supposed to smell differently to each of us, according to what attracts us, and I can smell freshly mown grass, and new parchment and - '

But she turned slightly pink and did not complete the sentence.

Dean lightly elbowed Cas to get his attention, while Slughorn was focused on Hermione.

'What do you smell?' he asked playfully.

Cas blushed but smiled. 'I smell fresh snow, apple blossoms, and - um - ' he lowered his voice. 'That cherry lip balm that you wear sometimes.'

Dean sniggered. 'I didn't know you knew about that,' he said. 'Glad you like it, though.'

'Well, well, take twenty well-earned points to Gryffindor, Miss Granger,' Slughorn said genially. 'Amortentia doesn't really create love, of course. It is impossible to manufacture or imitate love. No, this will simply cause a powerful infatuation or obsession. It is probably the most dangerous and powerful potion in this room - oh yes,' he said, nodding gravely at Malfoy and Nott, who were smirking sceptically. 'When you have seen as much of life as I have, you will not underestimate the power of obsessive love…

'And now, it is time for us to start work.'

'Sir, you haven't told us what's in this one,' said Ernie, pointing at a small black cauldron sitting on Slughorn's desk. The potion within was splashing about merrily; it was the colour of molten gold, and large drops were leaping about like goldfish above the surface, though not a drop had spilled.

'Oho,' said Slughorn. 'Yes. That. Well, that one, ladies and gentleman, is a most curious potion called Felix Felicis. I take it,' he turned, smiling to look at Hermione, who had let out an audible gasp, 'that you know what Felix Felicis does, Miss Granger?'

'It's liquid luck,' said Hermione excitedly. 'It makes you lucky!'

The whole class seemed to sit up a little straighter.

'Quite right, take another ten points for Gryffindor. Yes, it's a funny little potion, Felix Felicis,' said Slughorn. 'Desperately tricky to make, and disastrous to get wrong. However, if brewed correctly, as this has been, you will find that all your endeavours tend to succeed… at least until the effect wears off.'

'Why don't people drink it all the time, sir?' said Terry Boot.

'Because if taken in excess, it causes giddiness, recklessness and dangerous overconfidence,' said Slughorn. 'Too much of a good thing, you know… highly toxic in large quantities. But taken sparingly, and very occasionally…'

'Have you ever taken it, sir?' asked Michael Corner with great interest.

'Twice in my life,' said Slughorn. 'Once when I was twenty-four, once when I was fifty-seven. Two tablespoonfuls taken with breakfast. Two perfect days.'

He gazed dreamily into the distance.

'And that,' he said, apparently coming back to earth, 'is what I shall be offering as a prize in this lesson.'

'There was a silence in which every bubble and gurgle of the surrounding potions seemed magnified tenfold.

'One tiny bottle of Felix Felicis,' said Slughorn, taking a miniscule glass bottle with a cork in it out of his pocket and showing it to them all. 'Enough for twelve hours' luck. From dawn til dusk, you will be lucky in everything you attempt.

'Now, I must give a warning that Felix Felicis is a banned substance in organised competitions… sporting events, for instance, examinations or elections. So the winner is to use it on an ordinary day only… and watch how that day becomes extraordinary!

'So,' said Slughorn, suddenly brisk, 'how are you to win my fabulous prize? Well, by turning to page ten of Advanced Potion Making. We have a little over an hour left to us, which should be time for you to make a decent attempt at the Draught of Living Death. I know it is more complex than anything you have attempted before, and I do not expect a perfect potion from anybody. The person who does best, however, will win little Felix here. Off you go!'

There was a scraping as everyone drew their cauldrons towards them, and some clunks as people began adding weights to their scales, but nobody spoke. The concentration within the room was almost tangible.

Dean watched Cas hesitate ever so slightly before lighting the fire underneath his cauldron, then carefully cut up his valerian roots. Everyone else was working feverishly, but Cas was taking his time, measuring the pieces of root so that they were all exactly the same size.

'You're not going for the prize?' Dean asked curiously, adjusting his glasses on his face so that he could see the instructions.

'I think I've had all the luck I need,' Cas said, without looking up from his roots, and Dean bit his lip, fighting the urge to hug Cas. 'Besides, this takes practice. If you work on getting it right, speed will come later. You taught me that last year.'

'You're such a softie,' Dean teased, rummaging in his ingredients pouch for extra valerian root, as he had accidentally mangled the ones he was cutting up. It didn't surprise him that Cas wasn't going for the prize. Despite his talents, he had never been particularly competitive.

After about fifteen minutes, they both had potions that were a smooth consistency, and the colour of blackcurrant.

The instructions called for a few stirs before adding the juice of a Sopophorous Bean, so while Dean was stirring, he glanced around the room. Sherlock was working at breakneck speed, but when he turned away to get a bean, John, almost involuntarily, threw a handful of powdered asphodel into Sherlock's cauldron, causing it to fizz and emit thick black smoke.

Sherlock gaped at it, but John could only shrug, himself unsure of why he'd done it.

Molly giggled at Sherlock's expression. She too had decided on the slow and steady method, after deciding that she had no chance against Hermione.

Dean left his potion to sit while he cut up his bean, but Cas stopped him. He glanced around and picked up his bean. His eyes flashed blue and he crushed the bean in his hand, releasing more juice than it should have been possible for the shrivelled bean to hold.

Dean's mouth dropped open, watching as Cas dripped the juice into his potion. 'Castiel!' Dean said with a dramatic gasp. 'I can't believe you would do that.'

'It's not cheating,' Cas said with a shy smile. 'I'm simply using all the tools at my disposal. Give me your bean.'

Dean did as he was told and let Cas crush his bean for him as well.

Their potions both turned a shade of lilac, and all they had to do now was stir.

'How did you know to crush it?' Dean asked. 'The book says to cut it up.'

Cas shrugged. 'I saw Harry do it,' he said, nodding at Harry's potion, which was a lighter shade of pink than either of theirs.

'And time's… up!' called Slughorn. 'Stop stirring, please!'

Slughorn moved slowly between the tables, peering into cauldrons. He made not comment, but occasionally gave the potions a stir, or a sniff. He gave Sherlock a quizzical look at the thick potion still slightly smoking, but Sherlock just shrugged. He then moved on and gave Cas and Dean each an approving nod. At last he reached the table where Harry, Ron, Hermione and Ernie were sitting. He smiled ruefully at Ron's tarlike substance, and passed over Ernie's navy concoction. He smiled at Hermione's, then he saw Harry's and a look of incredulous delight spread over his face.

'The clear winner!' he cried to the dungeon. 'Excellent, excellent, Harry! Good lord, it's clear you've inherited your mother's talent, she was a dab hand at Potions, Lily was! Here you are, then, here you are - one bottle of Felix Felicis, as promised, and use it well!'

Harry slipped the tiny bottle of golden liquid into his pocket.

'How did you do that?' Ron whispered to Harry as they left the dungeon.

'Got lucky, I suppose,' Harry said, because Malfoy was in earshot.

Sherlock dawdled and, while no one was looking, syphoned some of Harry's potion into an empty phial and stashed it in his pocket.

John rolled his eyes, but said nothing.

It wasn't until they were safely at the Gryffindor table for dinner that he told them what really happened. He explained that the book Slughorn had leant him was covered in scribbled notes with alternative suggestions and instructions.

'I s'pose you think I cheated,' Harry said to Hermione at her stony expression.

'Well, it wasn't exactly your own work, was it?' she said stiffly.

'He only followed a different set of instructions to ours,' said Ron. 'Could've been a catastrophe, couldn't it? But he took a risk and it paid off.' He heaved a huge sigh. Slughorn could've handed me that book, but no, I get the one no one's ever written in. Puked on, by the look of page fifty-two, but -'

'Hang on,' came Ginny's voice as she joined them. 'Did I hear right? You've been taking orders from something someone wrote in a book, Harry?' She looked alarmed and angry.

'It's nothing,' Harry said reassuringly, lowering his voice. 'It's not like, you know, Riddle's diary. It's just an old textbook someone's scribbled in.'

'But you're doing what it says?'

'I just tried a few of the tips written in the margins, honestly, Ginny, there's nothing funny-'

'Ginny's got a point,' said Hermione, perking up at once. 'We ought to check that there's nothing odd about it. I mean, all these funny instructions, who knows?'

'Hey!' said Harry indignantly, as she pulled his copy of Advanced Potion Making out of his bag and raised her wand.

'Specialis Revelio!' she said, rapping it smartly on the front cover.

Nothing whatsoever happened. The book simply lay there, looking old and dirty and dog-eared.

'Finished?' said Harry irritably. 'Ord d'you want to wait and see if it does a few backflips?'

'It seems all right,' said Hermione, still staring at the book suspiciously. 'I mean, it really does seem to be… just a textbook.'

John sighed and held out a hand. 'Let me have a look.' he said.

Hermione hesitated, then placed the book into John's outstretched hand.

As soon as he touched it, he knew it was exactly what it appeared to be. 'It feels… a bit sad and lonely, and not all that pleasant, but nothing else,' John said, putting it down on the table.

'Are you sure?' Ginny asked anxiously. 'It's been a while since you saw the diary in person.'

John shuddered. 'Certain,' he said. 'I remember exactly what that thing felt like.'

Sherlock frowned. Even after all this time, he was still missing chunks of his memory from their second year, thanks to Gilderoy Lockhart's repeated use of the Memory Charm.

'Good. Then I'll have it back,' said Harry, snatching it off the table, but it slipped from his hand and landed open on the floor, revealing scribbled writing along the bottom of the back cover.

This Book is the Property of the Half-Blood Prince

He stowed it safely in his bag until they were back in Gryffindor tower.

Now that they weren't required to stay in their own dormitories, as they were the first night of the year, Sherlock moved his things to John's part of the room, and cast the Extension Charm on the bed, so they would both fit. John made no move to lie down, however, when everyone else had already gone to bed.

'You must sleep,' Sherlock whispered, draping a blanket around his shoulders.

John hugged his knees to his chest and stared into the fire. 'Maybe in a little while,' he murmured.

Sherlock nodded, but he too eventually fell asleep, his head on the arm of the sofa.

John watched him as he breathed steadily, and felt a twinge of jealousy that Sherlock did not have to experience the same pain and despair he did in his dreams. John nodded off briefly, but was again awoken by screaming and masked Death Eaters flashing before his eyes. He rubbed his face and sighed. He knew that Sherlock was right, but there was no sleeping, not like this. He cast his gaze about the castle, and caught sight of Cas's blurry presence in the hospital wing, already making a start on his Healing studies. John grimaced and forced himself to his feet, then made his way down to the hospital wing.

It was dark and quiet. No one had yet had need of Madam Pomfrey or Cas's talents, so the wing was empty but for Cas cataloguing the potions cabinet.

'Cas,' John whispered, approaching him.

Cas turned around, surprised to see him.

'Please help me,' he said, his voice cracking as he teared up. 'I can't sleep. I haven't slept. I'm so tired, you have to help me.'

Cas's expression softened, and he put a hand to John's shoulder. 'You can stay here for the night,' he murmured. 'I still have that list of potions that Sam gave me, I think I have something that will help.'

'Really?' John asked, desperate for something that would give him some peace, even for a few hours so he could finally rest.

Cas nodded and led John to a bed, passing him a set of pajamas to change into while he rummaged in the cabinet.

'Here,' Cas said, returning with a small bottle of magenta potion. 'This should help. Drink half of it now, and the rest if you wake up in the night.'

'Thank you, Cas,' John breathed, gulping down the potion.

'Goodnight, John,' Cas said softly, briefly bathing John in his soothing energy, before going back to his cataloguing.

John lay back on the bed, but the potion didn't work right away. He stared at the ceiling, and was about to give up, when he felt sleep wash over him. Deep and mercifully dreamless.