Author's Note: This is possibly the fastest I've ever spewed out a second chapter. Sadly, it's because I already had most of it written and I only needed to add a couple of hundred words. After this, it'll be back to insanely slow updates. Going back to uni does that.

Anyway, this chapter is less 'look at all the awkward stuff I have to do', and more 'my body and brain are actually confused now'. Because as if they wouldn't be. It's not like their brains actually switched bodies, just their consciousness, and I'm sure every part of them would get messed up as a result.

Mind Over Matter

The boys' dormitory was much the same as it had been every other time Lily had gone in there over the last six months: messier than the girls', though not explosively so; small, snuffling snores were coming from the bed closest to the window; and the curtains around Remus's had been ripped off during some misadventure eight weeks ago, leaving his sleeping form in plain view.

"Prongs?" a groggy voice said from the nearest four-poster. " . . . the hell have you been? I thought we were going through that essay tonight."

Lily groaned internally; she had hoped to sneak in quietly, without waking anyone, then get up first the next morning. "Sorry, Sirius," she muttered. "I forgot. We'll do it tomorrow, okay?"

"I did mine tonight anyway . . . You all right? You sound weird."

"I'm fine," she answered. Sirius mumbled something inaudible and trailed off.

One awkward trip to the toilet and some confusion about which toothbrush to use later, Lily made her way to James's bed. Of course, she wouldn't have been able to sleep even if that was what she wanted. She wasn't used to this body. She didn't know how to make it sleep. At least it was so dark that she could no longer tell how bad her vision was. Speaking of which - she removed her glasses. Best not forget about those.

Even though it was her idea not to tell anyone, and she definitely knew it was the best way to find the culprit, she hadn't stopped to wonder how it would feel lying to friends. It was harder than she expected not to just roll over and wake the boys up and tell them.

But wait, what if it was one of them who switched us?

She could definitely believe it of them. If it was Sirius . . . oh, she wouldn't give him the satisfaction of knowing it had worked. She was going to act her ass off.

She went over that brief interaction with Sirius in her mind, analysing it word-for-word, hitting herself for any small slip-ups she may have made. While it was true that Sirius probably wouldn't remember any of it, Lily had to make sure she sounded like James at all times. Prongs? he had said. Where the hell . . .

She actually slapped herself on the forehead. She had called him Sirius! James hadn't done that once in the entire time she and he had gone out! Padfoot, Padfoot, Padfoot, she recited to herself. And the others . . . Moony, Wormtail. Moony, Wormtail.

She was still reciting the names in her mind when she finally drifted off; her dreams were a tangled mess of her thoughts and a few she was positive didn't belong to her. When she drowsily woke up in the morning, it felt as if she had unlocked some dark section of James's brain that had long been closed off. How she had accessed it, she didn't know.

It was almost like a memory . . . was it possible for her to see into James's memory in this situation?

In the safety of the four-poster, Lily screwed up her eyes and tried to pinpoint this feeling.

The feeling of a wand twirling between her fingers . . .

Heart racing in excitement, disbelief . . . happiness beyond her wildest dreams . . .

And words, issuing out of her mouth of their own accord: "It's real. It's real. Lily actually said yes this time! I don't know what changed – is it because I'm Head Boy now, she sees I can be responsible? Whatever, I don't even care!"

She knew right away that these were real memories, not remnants of dreams. And the thought deeply unnerved her. No amount of Polyjuice Potion could have allowed her to witness another's memories; even a Pensieve wouldn't let her experience James's emotions in this way. Whoever had orchestrated this entire ordeal couldn't have known such a thing would happen, and she, Lily, had never even heard of such a thing being possible.

Suddenly, she felt sick with guilt. That was something she should never have felt, a privacy she had invaded worse than if she had made any number of sexual advances on James's body. Apart from the general wrongness of it all, they were broken up now. Her feeling any old love from James's perspective was horribly inappropriate and not at all what she needed right now. It was hard enough doing what she had to do. She had to forget that m

emory, ignore it completely.

Pulling aside the curtains of her four-poster, Lily climbed out of the bed, aware that nobody else in this dormitory had so much as budged from theirs. Once again, she almost forgot about her glasses. Then, after a brief moment's hesitation at the thought of what was to come, she shuffled her too-large feet to the showers.

They found each other in the hallway outside the Common Room without difficulty, even if it was about an hour earlier than James's usual getting up time (which wasn't saying much), and neither looked more than a little worse for wear, all things considered.

As they walked, they discussed in hushed whispers the logistics of what they had to do. Classes were a huge point – the bag Lily was carrying was exceptionally heavy because, not remembering which subjects James would have today, she had packed every book she could find – as was interaction with others. It pained James to accept that he might actually have to go out of his way to avoid detention.

Lily admitted her blunder when talking to Sirius the night before, but James wasn't too worried. A little name indiscretion was the least of his worries about what might come out during private conversations with the Marauders. That was one delicate area that James had felt still ought not to be shared, even after six months of blissful love.

Doing things properly, they decided to write down for each other all the information that would be necessary for them to keep up the charade. James grimaced as he finished scribbling out his timetable. Lily's petite hands didn't complement his handwriting very well, so many of the letters appeared very jagged. "Here," he said, handing it over. "We'd better eat quickly. McGonagall will kill me if it looks like I've missed another Transfiguration class."

The paper in hand, Lily turned ash-grey in the face and stopped moving. It looked as though James Potter was about to throw up.

"What?" the real James said irritably. She couldn't have possibly found his handwriting that repulsive.

"You do Arithmancy," Lily responded, voice filled with dread.

"Yeah . . . "

"I can't do Arithmancy."

James processed this, attempting to find a problem different from that with any of their other subjects. They each had their strengths and weaknesses: James wasn't as good as Lily at Potions or Charms, and Lily wasn't as good at Transfiguration or History of Magic. He had already accepted that this was one of those inconveniences they would have to deal with, one of those minor problems that would certainly impact them, but hopefully only to a minor degree. As long as they didn't have to do one another's exams, all they would have to do would be take notes for one another and recount the more difficult parts of the classes. This close to exams, however, most classes were unlikely to be doing much more than revision. It wasn't as though Arithmancy forced Lily to do unfamiliar magic in front of a whole roomful of people, and if she played her cards right, she could imitate James's uncaring attitude in such a way that meant she wouldn't have to do any actual work at all.

"Okay," James said slowly. "You just pretend you can."

Lily shook her head vigorously, hazel eyes wide with horror. "No, no, you don't understand. I can't. It's just not part of my genetic make-up to be able to function properly with numbers in front of me."

"I get it, but if you just hold it together and make a few notes for me - "

"I don't do numbers, Potter!" she shrieked. A portrait on the wall of Sombrius the Silent raised his eyebrows in bewilderment, but said nothing. Alarmed that someone else would hear his voice go into a panicked soprano, James hurriedly attempted to calm Lily down. Six months together, and he'd never seen her confronted with numeracy. She had even been confused enough to revert back to calling him Potter.

"Okay!" he hissed. "Stop it, stop it now. Just don't turn up. I know it all, anyway . . . You can't do this with everything, though. Under no circumstances can you skip Quidditch."

"Quidditch?"

Of course, there was more to being one another than classes and sleeping arrangements. Evidently Lily wasn't thinking one step ahead, and was just taking events as they came. It was most unlike her, James thought, but then he knew already that he was adapting better to this situation than she was. It was fair enough that she wasn't exactly strategising. He, on the other hand, had already figured out the best way to cover all his bases; unfortunately, some of them weren't going to be easy. He hadn't expected Arithmancy to be such an obstacle, so he wondered just how many more surprises were lurking in the near future for him. Quidditch had potential to be very problematic, but it also could have been a lot worse. There was only one match left, and it was against Ravenclaw, whose Keeper seemed to have a cold no matter how much Pepper-up Potion he took. The other two Gryffindor Chasers were good. Even without James, they could manage.

"I hadn't thought about that," Lily admitted, calm again now. The colour of her face began to return to normal. They began walking again, at a quick pace, until they made their way into the Great Hall and to their seats.

"Well, we can't miss the Grand Final. You'll be fine. What do you think of a strategy that involves - ?"

He was interrupted by a loud, "Make way!" as Sirius leapt onto the seat beside Lily, momentum carrying him so that he flew up to the table, narrowly avoiding a platter of fried eggs. Remus and Peter were walking drearily towards the table behind him, looking pained at the thought of being that active at this time of morning. Up at the teachers' table, Professor McGonagall glowered at the unsuspecting (well, maybe) Sirius.

"Morning, you two," Sirius said brightly, hopping down and settling into his seat. "Prongs, can you imagine my horror when I woke up at eight thirty and saw that you had already left? It was sacrilege, I tell you."

He was looking straight at Lily as he spoke, so there was no mistaking whom he was scolding. Lily was prepared enough for this, though. "Sorry," she said casually, abandoning James' timetable and beginning to get herself some breakfast. "I know you usually want me there to hold your hand while you shower, but I thought you should give it a try on your own at least once."

James cocked an eyebrow; it was definitely a very Lily-ish sort of insult, but the others probably wouldn't pick up on it. At least she hadn't sincerely apologised or anything silly like that. Sirius pretended to look hurt and huffed, "So, the deer bares its antlers."

"At least he has a pair," James responded smoothly. Sirius blinked.

"Prongs, you've been teaching her. I don't like it."

Breakfast went on for the remaining minutes without incident; Lily didn't slip up on her 'Padfoot's and her 'Wormtail's, and James made sure to look bewildered when Remus mentioned his 'furry little problem'. Luckily James and Lily had been so close during the last six months that any apparent similarities in the way they spoke was put down to them picking up each other's bad habits. They, along with the other three Marauders, ended up running five minutes late for Transfiguration, causing Professor McGonagall to deduct five points from Gryffindor each, but it left them feeling a lot more relaxed about being able to plausibly act like each other. Even their best friends couldn't tell.

In the class, everyone was put into pairs in order to transform magpies into mushrooms, putting the two of them together. Apparently Professor McGonagall thought Lily was a good influence on James's behaviour, and didn't object when they stood beside one another, the way she always did when James stood next to Sirius. The spell they were practising was non-verbal, so the class was in total silence apart from the occasional magpie cry, or the giggles that arose whenever somebody got the spell wrong.

This made Lily very visibly agitated; Transfiguration wasn't her forte, and occasionally she muttered insults at her magpie under her breath. "Stupid . . . Never did like birds . . . Where'd we get these pigeons, anyway? . . . "

"Not your best work, Potter," Professor McGonagall said as she circled the classroom, keeping them all in order. It was an understatement: Lily's magpie looked no more fungal than her face. Then, Professor McGonagall rounded on James. "And you still need some extra work, Miss Evans."

James looked at his work in surprise. He thought he had done the spell perfectly - but then he noticed his mushroom still had legs.

"That can't be right!" he said, aghast.

"You're certainly right about that, Miss Evans. Keep practising; it shouldn't take many more attempts." Professor McGonagall reversed the spell, bringing the ruffled-looking magpie back into existence, ready for another try. After she had turned her back, James looked at Lily in alarm.

"What is this? Why can't I do Transfiguration any more?"

"I'd hardly go that far," Lily said, scowling.

James ignored her. "I never screw up non-verbal Transfiguration spells! My wand movement's too good!"

"Well, maybe it's only good with your wand, rather than mine," Lily said sarcastically. James, on the other hand, froze.

He was using Lily's wand; it had seemed only natural that her wand would continue responding to her body, just like the Gryffindor staircase. But now it occurred to him that his assumption may have been wrong. Maybe, somehow, his own wand would recognise him.

He held out his left hand open-palmed, and used his right to toss Lily's wand toward her. She fumbled to catch it, earning a snicker from Sirius a few feet away. James eagerly grabbed his own wand out of her grasp, then turned back on his mushroom-magpie hybrid. Just to be safe, he whispered the incantation under his breath rather than relying solely on his wand movement, confident though he felt with it back in his grasp. It didn't feel quite right in Lily's hand rather than his own, but it was still familiar.

"Oh, wow, you actually thought that would help."

His own voice's sarcastic drawl was really quite annoying, he realised suddenly. Besides, Lily had no right to comment: switching wands had helped . . . marginally. There were no legs left this time, and it was just the general shape that was off.

"It's your body," he accused Lily. "Something's wrong with it, making my magic go haywire."

"What?"

"It's like . . . like 'the wand chooses the wizard' and all that, so my wand still recognises me, but it's my body that really does the work. Like – "

"Like your magic's in your blood, rather than your mind?" Lily finished for him. He nodded, bewildered. "Well, having magic is a real thing, not just a psychological state, so I imagine it would be part of your blood. But what on earth does that mean for us?"

James groaned. "It means we're screwed. I can't do Transfiguration as well any more because your body can't, and you can't do it because you and your wand aren't as good at it. We've got all the disadvantages of this, and none of the advantages."

He was dramatising, he knew: their work wasn't bad, by any means, but just bad enough to be inconvenient and a dead give-away for anyone who knew them. Not only that, but the lack of his own magic felt painfully debilitating, like he was really vulnerable now. What if someone attacked him and he couldn't defend himself properly?

Then Sirius flew his mushroom into Professor McGonagall's head and the room became chaotic.

When class was over and Lily and James left feeling extremely confused about their magic, Lily posed a strange question. "So, James, did you have any weird dreams?"

"Dreams? No, I never remember my dreams," he answered, bemused. Lily didn't look like she knew if that was the answer she wanted. "Why?"

"No reason. I just did, and I wondered . . . if it was a side effect or something. Nothing to worry about."

James's next class was Arithmancy, which Lily was promptly going to skip, while James himself headed outside to Lily's Herbology class. As he moved through the crowded halls, he found himself watching other girls and trying to imitate how they walked. It felt stupid and unnatural, but then everything about this felt unnatural.

Someone tapped him on the shoulder and he glanced over, expecting one of Lily's friends. Instead he saw someone he didn't recognise: a boy, probably in fourth or fifth year, though he towered over James as he was.

James almost said, "Who're you?" before stopping himself; if Lily knew this guy, that might give the game away. Instead he just said, "Yes?"

The boy didn't say anything, just walked alongside him all the way outside. He stood uncomfortably close and it was driving James mad with questions that he couldn't ask – who the hell is this guy? How does he know Lily? Why hasn't Lily told me about him? Why doesn't he back off a bit?

"You're awfully stiff, Lily," the boy commented eventually. James quickly tried to relax his posture: if this was some friend of Lily's, he didn't want to appear uncomfortable around him. Though this encounter was making him extremely suspicious, and shaking that feeling was not easy.

"Is there something you wanted?" James asked. He tried to keep his voice polite, but with an edge of warning to it. Don't try anything.

The boy's expression turned serious. "I wanted to know if that thing we were talking about happened."

James swallowed. "If it happened?"

"Did you do it or not?"

James desperately wanted a few minutes of total silence so that he could try to work out what was going on, but he didn't have that. The boy wanted an answer, and everything about his demeanour told James that this was not a casual conversation. This kid meant business. Normally James would've been more than happy to take him, but he didn't want to ruin Lily's reputation – plus, his magic might not have worked.

Instead, he didn't have a choice but to answer as quickly and vaguely as possible. "As far as I know, it happened."

Not good enough, apparently. Now that they had walked far enough that there weren't really other students around, the boy grabbed James by the shoulders and shoved him against a wall. In Lily's petite body, this hurt a lot more than usual.

"Hey! You know I'm Head B- " James corrected himself just in time. "Girl, right? Back off!"

The boy wasn't intimidated. "Did you do it or not?" he snarled.

"I'll rip you in – "

He loosened his grip on James for a second, only to push him against the wall harder. This time it caught James right in the back of the head and he saw stars.

"One more time, Evans. Did you, or did you not, do what you were supposed to do?"

Dazed, James was barely aware of saying, "Yeah . . . yeah, I did it."

He felt himself get dropped. Sliding to the floor, he blinked over and over again until his vision stopped swimming. He was full of rage, for himself and for Lily – how dare someone do this to her? He was going to kill this guy.

But the boy was long gone by the time James could make himself stand up. Lily's body was in shock; in the back of his mind, he realised this was a good thing, as it probably meant she wasn't accustomed to rough treatment. Maybe this was the first time this had happened. In fact, he was sure of it: he definitely would have noticed if someone had beaten her up before.

"Believe it or not, James, some people don't like me any more than you like the Slytherins."

James remembered Lily's words from last night with startling clarity. Was this what she meant? Did she think this guy was responsible for their body swap?

What exactly was she keeping from him, and how long had she been keeping secrets?

From where he was, James could see the entrance to the Herbology greenhouses. Weighing up the situation, he turned around and hobbled back in the direction of the rest of the school, intent on finding Lily in their Common Room and demanding to know what she knew. Hopefully she'd forgive him for skipping her class.