Harry wanted to tell Dumbledore what they'd learned.

Tom did not.

It sparked several furious arguments over the next few days. Harry had expected Tom to dislike the idea of course, but was surprised—and perhaps a little suspicious—at how nervous he became every time Harry brought it up. Harry would have been happy to do it without Tom's blessing, but he quickly found that the bond made it difficult. Dumbledore was never at the high table, and it wasn't possible to physically drag Tom to his office—Harry had tried. Finally, he forced the matter by stopping on the third-floor landing as they made their way up to the common room after dinner and refusing to move.

"Don't you dare," Tom said. "I haven't agreed to anything; it's none of his business."

"He's the Headmaster; of course it's his business that Voldemort has a bunch of Slytherins running errands for him in the castle. He needs to know to keep an eye on them."

"I'm not doing it."

"Are you worried we'll get in trouble? We haven't done anything too terrible, and he's let me get away with worse," Harry said, thinking of the time they'd used Petrificus Totalus on Neville in first year and left him on the floor all night. "A little bit of stealing, a bit of Stunning—"

"Yes, I'm sure he'd let you get away with murder," Tom said, "but what about me?"

"He can't punish you without punishing me too."

Tom folded his arms.

"Come on," Harry urged. "Why won't you let me?"

Tom grimaced, glancing left and right to be sure they were alone. "I'll tell you," he said, "but not here. Let's go back up to our dormitory."

Harry scoffed. "Nice try."

"You're such an idiot," Tom said. "Come on Harry, what do you think Nott, Crabbe and Goyle are looking for?"

"A weapon, maybe? Something to sabotage the school with? Some way to hurt Dumbledore? Some way to hurt me?"

"You can't die, remember? But no, I think it's something else."

Slowly, it dawned on Harry.

"You think they're looking for a—"

"Not so loud," Tom hissed, pulling him off the landing and into a shady nook underneath a carving of three crossed wands. "But yes. I think there's one in the school. I've thought that for ages, ever since we first started looking for them, but I assumed I would have placed it in the Chamber of Secrets, which, of course, we can't reach."

Suddenly, Harry remembered Tom's attempt to get him to fuck down in the Chamber. And that little tour of the Hogwarts passageways. He might have been genuinely horny, but he'd also been searching for a Horcrux or an escape route; so subtly Harry hadn't even realised he'd been doing it.

"There's always another level with you, isn't there?" he grumbled. "So what? You want to find it yourself? Are you going to try to absorb it? You haven't forgotten what happened last time you tried that, have you?"

"It'll be different this time; I know what to expect."

"What to expect?" said an arch voice. Harry spun around to see Professor McGonagall. She was standing at the mouth of the corridor with her arms folded. She'd snuck up on them so quietly that Harry had a sudden suspicion that she had been a cat until a moment ago—

"Expect from Slughorn's next delightful lesson," Tom snapped. "What are you doing here?"

"I am a teacher, Mr Novak," McGonagall said. "And therefore I have every right to be here. The question is why you are here, loitering in this corridor that leads only to the Headmaster's office?"

Harry let out a breath. She didn't seem to have overheard anything too suspicious.

"Are you following us around?" Tom demanded.

"The portraits told me you were here."

Tom glanced around, then scowled at a portrait of a pretty milkmaid standing on a raft in the middle of the ocean. The raft's other occupant—a mid-sized troll—was looking stupidly down at her. She blew a raspberry at Tom, then picked up her kegs of milk and strode out of the frame.

"We're here to see Dumbledore," Harry admitted, although now that Tom had finally come clean about what he thought Nott, Crabbe and Goyle were looking for, he wasn't sure if he did want to see the Headmaster.

"Professor Dumbledore is not in the school," McGonagall said. "In fact, he may not be present at all for the next few weeks. Before he left, however, he did leave me something for you, should you come looking for him."

Harry looked at Tom, shocked. Dumbledore couldn't have predicted that they'd abduct Malfoy, surely?

Tom shook his head.

"My office," McGonagall said.

They followed her down to the first floor, then to the end of the corridor that contained her office. It was a pleasantly-sized room, made cramped by the many towering stacks of books and parchment. They filled up bookcases and cabinets, encroached onto one side of the handsome oak desk and even spilled out over the armchair in the corner. Moving closer, Harry could see that one sheaf of parchment concerned the food coming into Hogwarts; another contained menus; and a third was a list of inspection dates for the school governors. Harry realised that with Dumbledore gone so often, McGonagall was effectively running the school.

"You can take your long nose out of my paperwork," McGonagall said smartly. Harry jerked back, but the expression on her face was rather fond. "Excessive nosiness is one of your faults, Potter. Or one of your strengths, perhaps. It's hard to tell."

"Sorry," Harry said, not really understanding.

McGonagall held out a small parcel wrapped in brown paper. Harry took it and turned it over in his hands. It was a book, he thought, about the same size and shape of Tom's diary. His excitement rose when he saw the looping green handwriting on the edge of the package: For Harry.

He could tell that McGonagall was just as curious as he was.

"Is it okay if I open it here?" he asked.

That earned him a small smile from McGonagall. "If you must."

Harry undid the string and tore the paper off. Even Tom was interested, peering over Harry's shoulder.

As expected, the package contained a book. The title read The Tales of Beedle the Bard. It seemed to be a children's book of some kind. Flicking through it, Harry found little illustrations depicting things like fountains and rabbits and cauldrons. His excitement turned to puzzlement.

"May I?" McGonagall asked. She took it back and checked it over for enchantments, running her wand along the seam several times. She frowned when she found none.

"What am I supposed to do with this?" Harry asked, trying to keep the plaintive note out of his voice.

"I don't know," McGonagall said. "Dumbledore didn't leave any other instructions. I can tell you that The Tales of Beedle the Bard is a common enough book, although this is an old edition of it. My mother read me some of these stories when I was a girl."

Harry grudgingly took the book back. He waited until they were down the corridor and out of earshot before complaining to Tom.

"What the hell?"

"Isn't it obvious?" Tom sneered. "He's putting you in your place, reminding you that you're a child and should keep your nose out of adult business. He used to do things like this to me all the time—like calling me by my first name during lessons and setting insulting exercises when I finished my work quicker than everybody else."

Harry knew that Tom was just trying to stir the pot, but it was effective. He'd come to see Dumbledore even though he knew it might get him into trouble; he deserved better than a book of fairy tales, didn't he?

Harry's irritated mood persisted until breakfast the next morning. He'd read The Tales of Beedle the Bard from cover to cover, but hadn't found anything interesting. There was a rather soppy tale about a fountain, a story about three wizards who meet the personification of death under a bridge, and The Warlock's Hairy Heart, about a warlock who locked his heart in a box. Harry suspected this last one might have been a coded warning about Tom, and didn't appreciate it.

He was sat next to Tom, sulkily eating his omelette, when the morning owls came. They descended on the tables in a great tawny flock. A handsome eagle owl landed in front of Malfoy, who cooed as he took the letter from its claws.

Harry stabbed his food with his fork, wondering if Voldemort would be hearing about today's dining choices.

There was a clatter from the end of the table. Harry looked up just in time to see Errol, the Weasley family owl, make a spectacular crash landing. The other Gryffindors hastily pulled their plates back as he skidded several feet, overturning dishes and glasses before he coming to rest on a platter of assorted jams.

"That blasted bird," Ron muttered, after apologising to Colin Creevy whose robes were now splattered with pumpkin juice. "What does Mum want now?"

But to their surprise, Errol shook out his feathers and then hopped in front of Tom. Tom untied the letter from his leg.

Ron looked gobsmacked. "Why is it for you? Hey, who sent you that?"

"Mrs Weasley, of course," Tom said. He scanned the letter quickly, and then pulled parchment and ink out of his bookbag to write a response.

"Why? Why is she writing to you?" Ron grew more panicked when Tom didn't answer. "What are you doing now? Harry, make him tell me!"

Harry was too busy trying not to laugh. He knew that Tom often posted letters to Mrs Weasley when Harry visited the Owlery to send his to Sirius, but he'd thought it better not to mention it to Ron.

"I'm only writing a reply," Tom said.

"WHY?"

"I write one every week."

"Every week? Every week?"

"Should I not?" Tom asked. "She seems to like it. She says you never write to her, Ron."

Harry wasn't sure when Tom and Ron had become on first-name terms, and by the horrified look on Ron's face, he didn't know either.

"What are you telling her?"

"Oh, we talk about the weather, school, your health, Harry's health, Granger's health," Tom said, tapping the feather of his quill against his chin. "I think I'll tell her that you got onto the Gryffindor Quidditch team—she'll be glad to hear that. Oh, and I suppose I should ask if she's seen Dumbledore."

Hermione's nose had been buried in a book about the history of wizarding accounting for the whole of breakfast, but at these words she looked up.

"What? Professor Dumbledore? Why?"

Tom turned to her. "Harry and I wanted to speak to him yesterday, but he wasn't in the castle."

Harry felt a sudden chill of foreboding.

"Why did you want to speak to him?" Hermione asked.

"If you weren't such a dreadful snitch, perhaps I'd tell you," Tom said sweetly.

They looked at each other for a long time; locked in a silent battle of wills. Finally, Hermione's curiosity won out over her pride.

"I apologised for that," she said.

"Not to me, you didn't," Tom said. He blew on his letter to dry the ink, then rolled it up and attached it to Errol's leg while Ron looked on helplessly. "It was very hypocritical too, Hermione, given what I saw you do at the Quidditch try-outs."

Hermione immediately dropped the subject and buried her head in her book again. Harry could see that her cheeks had turned a little pink. She didn't speak again for the rest of breakfast, but pulled Harry aside during morning break.

"Why did you try to speak to Dumbledore?" she hissed.

"What did you do on the Quidditch pitch?" Harry countered.

"Nothing!"

Harry raised his eyebrows.

"Oh very well," Hermione said. "I might have . . . I might have done something to McLaggen. But you can't tell Ron! He's a better Keeper than McLaggen anyway—I was just worried that he'd lose confidence in himself if he had to try out again."

"You Confunded McLaggen, didn't you?" Harry said indignantly.

Hermione checked to be sure no one was listening. They were in the open corridor on the ground floor that overlooked the grassy courtyard. Most of the other sixth years were nearby; Ron was talking to Seamus and Ernie out on the quad while Tom was perched on a wide stone windowsill with Parvati Patil.

"Yes, okay, yes I did," she said. "But that's not what's important right now. What did you want with Professor Dumbledore?"

"I thought Malfoy might be up to something," Harry admitted. "And perhaps his friends too—Nott, Crabbe and Goyle, I reckon."

"Why?"

Harry winced. He knew Hermione wouldn't approve of what they'd done to Malfoy, and that she would be offended and disturbed that he'd left her and Ron out of it. He suddenly wished he'd told her before stealing the potion—but it felt too late to come clean about it now.

"I just do," he said lamely.

Hermione looked doubtful.

"See?" Harry said. I knew you wouldn't believe me."

"It's not that I don't believe you," Hermione said. "It's just that you always think Malfoy is up to something . . ."

"Yeah, and last year I was right, wasn't I?"

"I suppose but—" Hermione broke off. "Wait, you haven't been stalking him or anything, have you? You and Riddle keep sneaking off by yourselves."

"No!"

Hermione narrowed her eyes.

"Don't think I haven't seen the two of you looking at the Marauder's Map together," she said coolly. "And since when does Riddle know about that, by the way?"

"I told him a couple of weeks ago," Harry muttered.

"Of course you did," Hermione said, rolling her eyes. "Well, I'll help you keep an eye on him—them—if you like, but I don't see what harm a bunch of rather stupid sixteen-year-olds can do."

Harry stomped off to join Tom, who was looking rather smug.

"You did that deliberately," he said when Parvati left.

"Oh?"

"You dropped Dumbledore's name to force me to lie to Hermione."

"You could have told the truth," Tom said slyly. But he must have known that Harry wasn't ready to do that. It was why he'd let it slip: to force the confrontation before Harry was prepared.

"You're trying to show me that no one else is going to have as much fun sneaking around with me as you."

"Yes," Tom said. "If you tell them, they'll want us to stop, or they'll insist on going to a teacher, which means the Horcrux will be destroyed. Now, speaking of sneaking around, have you got the map on you?"

"Why?"

"I think we should break into the Slytherin dormitories and look through their things."

Harry grimaced. He liked that idea. He liked it a lot. But he also felt as if things were moving too fast. Normally Harry was the reckless friend—the one coming to Ron and Hermoine with a dangerous idea. But Tom was just as reckless as he was, which meant the dynamic was reversed. It was freeing, but it also felt as if they were constantly daring each other to go faster, to do more. Right now their goals were aligned, but they wouldn't always be.

"Let me think about it," he said.

"Why?"

"Because you're getting your own way too often. It's going to your head."

Tom didn't look impressed.

"If we do this," Harry said, "I want some kind of concession."

"A concession for something you want to do too?" Tom said incredulously. "I can tell you do—don't think I can't read you like an open book nowadays.

Harry sighed theatrically. "Then I guess you'll have to wait."

"What do you even want?"

"I don't know," Harry said, glancing at Parvati to make certain she was out of earshot. "How about, next time we go to the Ancient Runes classroom after lights out . . . you let me put it in."

Tom laughed as if this was the most ridiculous thing he'd ever heard. "No way."

"Why not?"

"It's not really my thing."

"Fine," Harry snapped. He was insulted that Tom had laughed at him. "I'm going to watch them on the map. You can do whatever you like."

"Don't be like that, Harry," Tom said cajolingly. "Breaking into their dormitories will be much faster."

"Why? What are you expecting to find? Do you think they've already got the Horcrux?"

Tom shrugged. "Maybe. Or perhaps they'll have some notes, lists of locations where it might be."

This explanation sounded very flimsy to Harry.

"Or we could wait for Dumbledore to come back."

Tom scowled. "He'll destroy it."

"And you'll absorb it." Harry frowned. "What are you going to do when you've got all the pieces?"

Tom didn't answer.

"It's all about leverage, isn't it?" Harry mused. "You mentioned that to me before. The more of them you have, the more Voldemort is going to want you alive."

"So what? It's important to hedge your bets."

Harry wasn't convinced that this particular hedge was in his own best interests. Tom wanted to survive, but Harry did too, and he wanted Ron and Hermione and everyone else he cared about to be alright. The two outcomes were almost mutually exclusive. He was also still haunted by the incident with the locket; Tom's red eyes and cold voice.

"Wonderful," he said coolly.

"Dumbledore gave you a book of fairy tales," Tom sneered. "He doesn't care; he's abandoned you."

"He's probably off looking for Horcruxes right now," Harry said, with a pang of guilt.

Tom shook his head. "I expect he's too busy propping up the Ministry."

"Huh?"

"Haven't you been reading the Prophet?"

Harry wished people would stop saying that.

"I read it, okay?"

"You skim through it looking for news about you or Voldemort; I've seen you do it."

"So what?" Harry said defensively.

"If you were reading it properly, including all the boring political articles you normally skip, you'd know that Scrimgeour is in a very shaky position. He was a competent Auror, but he mostly worked out in the field, and isn't a good enough administrator to handle a war. The Wizengamot is in open revolt—he'll be lucky to last until Christmas. Maybe not even that long if something else happens. And it will."

Tom was proved right two days later when Harry came down for dinner to find the room silent. He didn't even need to ask what had happened; he knew.

"Same again," Ron said, giving him a copy of the Evening Prophet.

Harry forced himself to read the whole article this time, and all of the analysis that came afterwards. It was a hamlet in the Scottish highlands; some twenty or so families, all Muggle. They'd been brought out onto the dual-carriageway and murdered where they stood. Looking at the pictures made Harry feel hollowed out, as if someone had taken his guts and organs and blood and put them in a jar somewhere. It just seemed so pointless.

Or perhaps pointlessness was the point. Voldemort was saying, look, I don't even need a reason to kill people.

At the Slytherin table, Goyle was laughing at a joke.

"Okay," Harry said to Tom. "Let's do it."

They skipped Charms the next day. Harry knew they'd get detention for it, but it was the only class that all the Slytherin boys were taking, and therefore their best shot of getting into the dormitories undetected. Tom led Harry down to a spot in the dungeons, where they loitered under the invisibility cloak. When the bell rang for class, the blank stone wall opposite opened and several younger Slytherins hurried out. Harry and Tom waited for the last one to leave, then slipped inside before the entrance could close.

The common room was empty. It was long and rectangular, with a vaulted ceiling that made it feel a bit like a crypt under a church. Tall windows lined the longest wall, and pale green light shone from them. Harry drifted towards them, fascinated. The room was below the surface of the lake, and he could see tangled columns of weeds drifting in the current, darts of light as silver fish sped past. It should have been eerie, maybe even menacing, but something about the view was actually quite calming.

"Do you like it?" Tom asked.

"It's alright," Harry said, looking around at the rest of his surroundings. The squashy armchairs were the same as the ones in the Gryffindor common room, only emerald green rather than red. They were arranged in clusters around the room, with half a dozen around the central fireplace. Tables and chairs for studying were tucked into stone alcoves cut into the opposite wall. It was much tidier than Gryffindor tower, which was always littered with an ample supply of sweet wrappers, odd socks, and merchandise from Weasley's Wizard Wheezes.

"The dorms are up here," Tom said, leading him towards an archway at the end of the room. Beyond it was a mahogany spiral staircase. Harry and Tom kept the cloak on as they climbed it, intermittently checking the map to be sure they weren't surprised.

"I think it's this one," Tom said finally, stopping outside a door three stories up. The brass nameplate read: V. Crabbe, G. Goyle, T. Nott, D. Malfoy & .

Harry was immediately surprised by how bright the room was. It was above the surface of the water, he realised, but only just—there were tidemarks reaching halfway up the windows. There were five four-poster beds; two on the left-hand side of the room and three on the right. Like the staircase, they were dark, polished mahogany, decked with white and silver hangings.

Tom closed the door behind them and then ducked out from under the cloak. He walked around the room with a definite air of familiarity.

"This was my dorm in fourth year," he explained. "I slept in that bed there, the one under the window. Abraxas had the one next to it."

"And which of those did you sleep in?" Harry asked dryly.

"Jealous?" Tom asked slyly, sitting down on the bed that had once belonged to Abraxas Malfoy. He looked at Harry speculatively, then patted the mattress beside him. "How about we test it out? They won't be back for an hour."

Harry gave him an incredulous look.

"Are we here to search their things or not?"

"Fine, suit yourself," Tom said.

Going by the names on each trunk, Malfoy, Crabbe and Goyle were on the right-hand side of the room, while Nott was in Malfoy's grandfather's old bed and Zabini was in Tom's. Harry wondered briefly what Zabini would think of that fact, if he knew. He searched underneath their pillows and beds while Tom dismantled what he said was a fairly pathetic charm on Nott's trunk. By the time Harry came back, he was taking objects out one by one, inspecting each one and then laying it on the rug in a careful pattern so he could remember where they'd come from.

Tom's movements had a suspiciously practised air, and Harry was reminded of his little collection of stolen objects at the cottage. Was it still tucked safely under the bed?

The thought of the cottage, of the humble little bedroom with its uneven walls and sagging mattress, brought a prickling rush of nostalgia. Harry remembered the patched quilt and pillows, and the shelves of books whose titles he had read on lazy mornings when he couldn't be bothered to get out of bed.

A metallic clink sounded, and he looked up to see Tom weighing what looked like a bag of Galleons in his hand.

"Don't steal anything."

"I wasn't going to," Tom said. He put the money down and began hurriedly testing a quill to see if it had any magical properties. Harry rolled his eyes. He thought Tom was being a little more thorough than he needed to be, seeing as he would have sensed a Horcrux if there was one in the room.

When Tom reached the bottom of the trunk, he frowned and felt over the base, as if looking for hidden compartments.

Harry shook his head and went over to search Crabbe's belongings. His trunk was dark blue and expensive-looking, with a silver nameplate. The neat exterior belied the jumbled mess that lay within. Harry wrinkled his nose as he fished a mound of rather smelly clothes out. Underneath were sweets, trinkets, and half a dozen textbooks that looked as if they'd never been opened. Harry grimly moved them out of the way (now convinced that this entire trip had been a total waste of time) and sorted through the detritus at the bottom—mostly squashed chocolate frogs, dead insects and Quidditch memorabilia.

Then, under a frayed Wimbourne Wasps scarf, he found a small pine box. He opened it without much enthusiasm.

For a moment, he couldn't understand what he was seeing.

Vials.

Dozens and dozens of them, all jumbled up together. Some of them were empty, but of the remainder, half contained an electric blue liquid, and the other half a warm bronze. Harry couldn't identify either potion, but he was absolutely certain that Crabbe wasn't supposed to have them.

"Tom!"

Tom looked up from Goyle's trunk.

"Oh?" he said. Then his eyes fell on what Harry was holding. "Oh. Now that is interesting."

"What are they?" Harry asked as Tom held one of the electric blue vials up to the light.

"No idea," Tom said. He uncorked it and sniffed, then did the same with one of the bronze vials. "I think it might be Polyjuice potion."

"I know what Polyjuice potion looks like," Harry said, thinking of the mud-like sludge that Slughorn had shown them in their first lesson, "and it's nothing like that."

"That's what it looks like before any hair is added. It looks completely different afterwards."

Harry still wasn't convinced. But as he dug through the bottom of the box, he found two small envelopes. He opened one and found it contained blonde hair. "Oh."

"It's been pre-set," Tom said.

"So what, Crabbe is impersonating two people? A lot of these vials are empty."

"Maybe . . . or maybe the three of them take turns," Tom said. "We need to find out who the hair belongs to."

"And how do we do that?"

"You aren't going to like it."

"What?"

"We need to drink it."

Harry grimaced. The last time he'd drunk a random potion at Tom's behest, it hadn't turned out so well for him.

"I'll take one too," Tom said quickly, perhaps also remembering the incident in the cave. "This is the only way."

Harry still wasn't happy, but he pocketed two vials—one in each colour—and then slid the box back underneath the scarf. He repacked the trunk while Tom finished searching Goyle's, without result. They closed the lids and pulled the cloak back over their heads, leaving the Slytherin dormitories with twenty minutes to spare.

Once they were back in the dungeon corridor, Tom led him to the closest boys' toilets, a small room on the ground floor. Like most of the toilets down here, it was grotty, with a cracked mirror, a row of urinals and two toilet cubicles, one of which was out of order. They crammed themselves into the other one, manoeuvring awkwardly to close the door. Tom dropped the lid on the toilet and sat on it.

"And you're sure this is Polyjuice potion?" Harry asked as he pulled out the two vials again. "I don't want to end up poisoning myself."

"You saw the hair," Tom said sensibly. "And it smells like Polyjuice potion."

Harry sighed. "Fine. Which colour do you want?"

Tom didn't have a preference, so Harry chose the bronze vial for himself and gave him the electric-blue one. Bronze seemed safer. They uncorked them together, met each other's eyes, and then both drank at once.

To Harry's relief, it didn't taste too terrible. More like black pepper than anything else.

No sooner had he swallowed than a crunching, popping sound split the air. Harry suddenly dropped six inches in height; he clutched at the wall for balance. He could feel his skin shifting over his bones, his feet shrinking in his shoes. Then, with a tugging sensation, long brown hair sprouted from his head, masses of it, growing and growing until it reached past his shoulders.

When it finally stopped, Harry pushed the hair out of his eyes. He was amazed at the change in perspective; the top row of mauve tiles was now just below eye level, as was a line of graffiti suggesting that Snape's mother had done something terrible with a Flobberworm. He looked quickly at Tom, wanting him to share in this revelation—

There was a little girl perched on the toilet seat where Tom had been, sitting with one knee crossed over the other. She had bouncy blonde curls and a stubborn chin, and must have been about eleven or twelve years old. A comically oversized shoe dangled from her tiny foot.

And on her face she wore a disdainful expression that was utterly, unmistakably Tom.

Harry let out a giggle which sounded nothing like his own voice. This made him giggle even more. He stepped backwards, then promptly had to grab onto his trousers to stop them falling down.

Tom sighed.

"Right," Harry said when he finally got his hysteria under control. "Right. We're little girls. Okay." He tightened his belt, threading the buckle through the very last hole, then stepped out of his shoes before he could trip. The cubicle seemed much bigger now.

"Leave your belt," Tom said. "Otherwise you'll get hurt when you turn back."

Harry frowned—there was something grating about being bossed around by an eleven-year-old—but reluctantly unbuckled it. He pushed his hair out of his eyes again, then smoothed down his shirt.

Wait. Was it weird for him to be touching his body? It was weird, right? His thoughts skittered to a horrified halt when he realised that there was something strange between his legs. Something he wasn't used to at all; that he hardly dared to even picture—

Then something even worse occurred to him.

"What is this for?" he demanded. "Why does Crabbe have Polyjuice potion that makes him look like a little girl? What the fuck?"

"I imagine it's for spying," Tom said calmly. He seemed utterly unconcerned by the sudden changes in his body. "Looking like this would allow him to get into places that would otherwise arouse suspicion. Hm. Do you recognise me? You look vaguely familiar but I can't place you."

Harry shook his head, although there was something familiar about the little blonde girl. Perhaps he'd seen her Sorting.

"Well, think about it," Tom said. "We'll be like this for some time."

Harry nodded and crouched down with his back against the door, hugging his new, not-very-knobbly knees to his chest. Tom rolled up the ankles of his trousers and settled in to wait.

"It's a pity we're not older," Tom said after a while. "If we were, we could do something fun."

It took a moment for Harry to understand what he was getting at. When he did, he was not impressed.

"God, you're so horny today," he said. "And I wouldn't do that anyway—not in someone else's body."

"Why not?"

Harry didn't know how to explain the concept of invasion of privacy to Tom, who was shameless about his own body and probably thought everyone else was very strange for not feeling the same way. They lapsed into silence, only looking up when they heard someone else come into the toilet. Whoever it was waited for a minute, then tapped pointedly on the door to their cubicle.

"IT'S OCCUPIED!" Tom shouted.

"Are you a girl?"

"Are you an idiot?"

The boy swore at them but left. Harry, who had moved when the boy came in, settled back against the door, now looking at Tom's face. The longer he looked, the more familiar the blonde girl became.

"Hang on a moment . . ." he said. "Remember those little girls we helped a few weeks ago? The pair on the seventh floor who needed directions to the Astronomy Tower?"

"Yes," Tom said slowly. "Yes, yes, that's it! And you look like the brown-haired one! I'm sure I've seen her around the castle since . . . always on the seventh floor, outside—"

They got it at the same moment. Tom smacked a tiny fist into the palm of his hand.

"The Room of Hidden Things."