4. The wait for a storm may take weeks, months or even years. During this time, the crystal phial should remain completely undisturbed and untouched by sunlight. Contamination by sunlight gives rise to the worst mutations. Resist the temptation to look at your potion until lightning occurs. If you continue to repeat your incantation at sunrise and sunset there will come a time when, with the touch of the wand-tip to the chest, a second heartbeat may be sensed, sometimes more powerful than the first, sometimes less so. Nothing should be changed. The incantation should be uttered without fail at the correct times, never omitting a single occasion.

• • •

"You," said Snape, his beady little eyes fixed on James in an expression of utmost loathing. "You're up to something."

They were standing in the narrow hall outside the Potions classroom. Twenty minutes before, James, Sirius, and Peter had run out of Professor Slughorn's lesson, making it to a quiet classroom just before the sun set. Slughorn had only looked at them bemusedly; he was fond of all of them except Peter, who had no talent for potions, and Sirius commented that he probably didn't care where they were going as long as they made it to the next Slug Club meeting.

Remus, bent over his cauldron, watched them leave, his eyebrows creased, but said nothing.

They had performed the incantation, which, by now, James was sure he could have said in his sleep. Amato animo animato animagus! As always, nothing happened. As always, James couldn't suppress a slight shiver at the thought that they might have been doing it wrong this whole time.

Then they had emerged to find Snape, his greasy hair trailing over his shoulders, stabbing a stubby finger at them as though they had just admitted to slipping toothpaste into his breakfast tea.

"Maybe nobody else has seen it, but I have," declared Snape. James hadn't thought it possible, but Snape's eyes narrowed even more. "You've been acting weird—not weird; bizarre, even by your usual standards—for months. You're planning something. I'm going to find out what it is."

"The only thing we've been planning," said Sirius, "is how best to get that stupid nose of yours to a Muggle surgeon, Snivellus."

"I see someone's been paying attention in Muggle Studies," Snape said. "Wilkes was telling me about how he used to come round to your house before Hogwarts. How your mum used to beg him and Mulciber to keep you company. How you were a dirty little blood traitor even then."

Twin spots of scarlet were blossoming on Sirius' cheeks. James knew the memory of the letters he'd received from his mother were still fresh. James hadn't read them—he'd watched Sirius set fire to them only minutes after receiving them—but he thought he had a pretty good idea of what they had said.

Sirius withdrew his wand from his pocket. Snape copied his motion.

"At least I know what I am," Sirius hissed. "At least I'm proud of it. Not like you, Snivellus. Do all those blood purists you hang out with know you're only a half blood? Did you tell them about your dad yet? I suppose they all think your mum couldn't do any better for herself, what with that great honking nose on her. Mind you, I suppose she didn't realize your dad would make it worse—must have a few hag ancestors; all you need is to look at you—"

"Don't you dare," said Snape. His voice had gone cool and dangerous. "Don't you dare—"

He and Sirius cast their curses at the same time. Peter ducked, covering his head with his hands. James whipped out his own wand and pointed it at Snape, but it was already too late; they were already fighting in earnest, and there were too many flying spells for him to aim safely.

"Relashio!"

"Petrificus totalus!"

"Densaugeo!'

"Rictusempra!"

"EXPELLIARMUS!"

This last spell didn't come from Sirius or Snape, and it took James a moment to realize who had cast it. It was only when he saw Remus that he understood. He was standing just behind Snape, in the doorway of the classroom they had used for the Animagus spell. He was also holding Snape's wand.

"I'll give this back," Remus explained, brandishing it at Snape, "if you get out of here."

Snape stared at him. Remus stared back, his eyebrows very slightly raised.

"Your dormitory's down that way," he said. He gestured at his prefect's badge, the one James had only ever seen him trying to cover up with the folds of his cloak. "Do you want me to report you?"

Snape gave Sirius a look of unmistakable hatred. "This isn't over," he muttered.

"No," Sirius agreed. "It isn't."

Snape plucked his wand out of Remus' hands, tucked it into his robe pockets, and stalked off, leaving James and Peter to gape after him.

"Remus," said Peter slowly. "Er."

Remus did not meet any of their eyes. He was worrying at his lower lip, his expression focused on a crack in the stone wall where a spider was dangling by a thread.

"Ahem. That room. The one you're standing in," said James, trying and failing to think of any way Remus might have followed them to the classroom where they'd performed the spell without their noticing. "When did you… get there?"

Remus looked at James. There were dark circles beneath his eyes, despite the fact that the full moon was weeks away. He opened his bag and pulled out James' Invisibility Cloak.

There was a prolonged, awkward silence.

"You heard us, then," said James. "The spell we did."

Remus gave a brief nod.

James consulted Sirius and Peter briefly with his eyes. They both looked just as unsure as he felt. Sirius glanced at Remus, and James understood what he was thinking.

Do you think he knows what the spell does?

"There are rules, for it," said James, trying to feel out how much of the truth he should reveal. "We have to do it perfectly. We have to cast it every sunrise and sunset, and we can't miss it even once. That's why we've been gone so much. We'd have explained it to you; we were going to, except…"

"The spell," said Peter unhelpfully. "It's a bit… there are things…"

We have to tell him, said Sirius' eyes. We don't have a choice anymore.

I know, James tried to say. But I don't know how.

"It's complicated," said James, feeling as if he was about to plunge headfirst into kappa-infested waters. "Really, really complicated. We'd have told you. We were waiting for the right time to tell you. But."

"It was going to be a surprise," said Peter.

"Look, mate," said Sirius abruptly, and made the decision for them. "We're becoming Animagi. The three of us are. For you."

Remus looked at him as if he had gone madder than his great-aunt Cassiopeia, who was currently convalescing in a Home for Reality-Challenged Witches.

"It's a really fiddly spell," said James, aware that he was about to start blathering, but unable to make himself stop. "Well, really it's a potion and a spell. We've had to do all sorts—there were the Mandrake leaves, first of all—that's what they were, you know, they weren't cabbages. And then we had to get this dew from the centaurs—they really didn't want to talk to us, but we got it anyway—we went while you were in the hospital wing. And Sirius' Uncle Alphard is still convinced he's whipping up Love Potions because of the chrysalises we asked him to send—"

"I've had to make up a girlfriend," said Sirius. "Don't want to disappoint the poor man. Mehitabel, I've named her. Hitty for short."

"I told the centaurs I wanted to be a flea," said Peter proudly. "I don't, of course. I'm hoping more for an otter. They always look like they have such fun swimming."

"That wouldn't be much use against a wolf," said Sirius, frowning at Peter. "I'm hoping for a bear, myself."

"Hang on just a second," said Remus, suddenly paling again. "Wouldn't be much use against a—what are you trying to do?"

"We're not trying, we're doing," said Sirius, with a kind of confidence that James did not feel. "We've nearly got it, we're just waiting for—well, anyway. We're going to become Animagi, and then we're coming to the Shrieking Shack with you. To keep the wolf company. To make things easier. The books all say transformations go much better if the wolf is with a pack."

"And there's no way it can hurt us," said James, operating under the vague hope that the look on Remus' face would grow milder if they only kept talking. "Werewolves only care about humans, right? They do, that's what all the books say, we've read dozens of books, the library doesn't even have all the books we've read. And we won't be humans, we'll be animals, so we'll be fine. It's brilliant, isn't it? Isn't it? Sirius thought of it, but we'd been trying to come up with a way to help for ages."

"And then you won't, you know, hurt yourself like you do," said Peter. "Because you'll have us."

"You're mental," said Remus hoarsely, looking from James to Sirius to Peter as if he expected them to jump at him, waving a knife. "You're all completely mental. How long have you even been—"

"Since second year," said Sirius, grinning.

"Since we found out, pretty much," James admitted.

There was a small, and yet somehow still prolonged, sort of pause.

Then Remus put his hands over his face, took them off, stared at his palms, shoved them into his pockets, and began pacing down the hallway, his back turned to them. They watched him go, hoping he would turn around when he reached the end of the corridor. He didn't. He merely stood there, his shoulders clenched.

"Should we follow?" whispered Peter.

James felt very strongly that they shouldn't.

"He'll come back," he said. "Just—just wait a minute."

He did, but it took more than a minute. In that time, the three of them stood frozen, looking at their shoes, because it would only make things worse, James felt, to look at Remus; he was sure he would somehow be able to feel their eyes on his back. They stood like that for so long that James almost jumped when Remus' footsteps suddenly sounded from just a few feet in front of him.

James tried to arrange his face in such a way that Remus would be unable to tell what he was thinking, what he was hoping. But James didn't have that sort of face.

"How close are you?" said Remus, his voice very quiet. "You said you were close."

"There are just a few more things we have to do," said Sirius, too jauntily. "Bits and bobs, here and there. It could take a while, but I've decided it won't. Anyway, it's all downhill from here; the hard bit is done. Except for the spells. Got to do that until the end, apparently."

"Right," said Remus. "So… now that I know about the spells, I could stop you from doing them. Take your wands while you're sleeping and only give them back at breakfast. That would ruin the whole thing, right? The whole spell? So you'd have to stop."

"No," said James, because that was one thing he knew. "We'd only have to start over again."

"Yes," said Peter.

"Exactly," said Sirius.

Remus looked at the three of them. Remus did have the kind of face that was, at times, unreadable.

But then something quirked at the corner of his mouth.

"So what you're saying is, I can't do anything to stop you. No matter what I tell you. You're going to become Animagi regardless." He folded his arms in a rather trembling way. "Even though it's fiddly and difficult and the worst and stupidest idea I've ever heard in my life."

"The boy is brilliant," Sirius remarked. "Top marks."

"No," said Remus. "I mean it. Is that what you're telling me? Is that exactly what you're telling me?"

"It's exactly what we're telling you," said James.

Peter did a nod that was his peculiar specialty, a kind of adamant nod that went on for much longer than nods usually do. Peter, James reflected, was nothing if not loyal.

"Right then," said Remus, and suddenly there he was smiling again, as he had not smiled in weeks, and James knew, with a blast of relief not unlike the force of the spells Sirius had thrown at Snape, that it was going to be all right.

• • •

They were in the empty classroom again. Remus stood guard outside the door.

"Amato animo animato animagus!"

Once again, they spoke the words in unison, their wands placed over their hearts as the sun made its daily journey above the horizon, giving Scotland its few much-needed hours of sunlight. Once again, nothing escaped from their wand tips, just as nothing was supposed to. And once again, they breathed a sigh of relief, one that hid only a tinge of disappointment.

But this time something was different.

It started off very faintly, and at first, James was sure he was imagining it. Still, he kept his wand where it was, even as Peter and Sirius began to gather up their things and prepared to head to breakfast. No, James thought… he wasn't imagining it… was he? It was there. It was. He was sure he could feel it.

As soon as he thought this, the feeling became much more pronounced, and then he was sure. He took in a sharp breath, stuck his wand in his back pocket, and put his hand over his chest instead. Two heartbeats. Not just one; not anymore.

"Guys," he said, trying not to sound too panicked. "Guys."

When Remus came into the classroom ten minutes later to find out what was taking them so long, it was to discover his three best friends with their hands clasped over their chests, as if about to take some kind of solemn, life-altering vow.

"As far as I know, only Americans do the Pledge of Allegiance," he said, glancing them over. "But I suppose it's none of my business if you've decided to abandon your country."

"It's so strong," said Sirius, his voice awestruck. "Like, stronger than my real heartbeat, I think."

"Maybe I messed it up," said Peter nervously. "I think I can feel mine, but—but it's really small. Faint. Do you think I did something wrong?"

"You did everything we did," said James. "If you did something wrong, then we all did something wrong, and we didn't, Peter. We can feel the heartbeats! The book said loads of people never get this far."

To him, the heartbeats felt entirely equal. It was impossible to tell which one was his and which one belonged to the animal that was slowly making a home somewhere within him. He didn't care which was which. The sun was high in the sky now, and all of Saturday stretched before them. Remus clearly still had no idea what was happening, but there must have been something about it that he found amusing, because his lips kept twitching.

"Amato animo animato animagus," James muttered to himself. Maybe he did understand what it was supposed to mean.