Everyone makes mistakes. Sometimes little, insignificant ones, sometimes life changing ones. For Peter to find out what led him down this path, he's going to have to remember his mistakes.

1.

The Sorting Hat took a long time Sorting Peter. Eleven years old and completely terrified, he walked to the platform where the hat sat much in the same way one might walk to the gallows. His mother, a tall, cold woman, had been Sorted into Ravenclaw, and his father, small and earnest, had been a Hufflepuff.

When the hat was put on his head, it started talking at once.

"Let's see, let's see. You're a difficult one, aren't you. You don't seem particularly keen on book smarts, so Ravenclaw's not for you. Perhaps Hufflepuff? Well, maybe, but something seems off about that. You'd only get picked on in Slytherin. Gryffindor might do. You're not particularly brave, but you're not a coward, and I've seen bravery grow. You'd probably be treated best there, too. Would you like to be a Gryffindor?

Peter wasn't sure. Truth be told, he hadn't given it much thought. But Gryffindors were brave, right, like the heroes in the books he read? Peter wanted to be a hero. And he was feeling so scared right now, and he really, really wanted to feel brave.

"Well, that's settled, then. Gryffindor!" the hat said out loud. Peter walked to his table amidst applause.

He'd never been applauded before.

2.

"No, absolutely not."

"Come on, Peter," James wheedled. "Just put on the robes."

"They're women's robes. Pink women's robes."

"Well, it's not our fault your birthday's on All Hallows."

"Do Muggles actually dress up for that?" Peter looked to Remus for help.

"Yeah. My parents took me out for All Hallows every year as a kid. They wanted me to have every experience I could in the Muggle world, in case—" He turned beet red and stopped talking.

Peter was dying to ask Remus to finish his sentence, but there was a more immediate matter at hand. "All Hallow or not, I'm not wearing them. The girls would take the mickey out of me. Besides, I'm older than you now. You can't boss me around."

"Come on, Peter. It's your thirteenth birthday. Look at this as a rite of passage."

"How did you get pink robes, anyways?" Peter asked, hoping to distract James.

"Sirius transfigured them."

Peter looked over at Sirius, who was lying across his bed watching the scene. "But that's really advanced magic!"

Sirius pushed back his hair from where it had fallen in front of his face. "You forget, my father couldn't give a rat's arse about underage magic restrictions." Sirius always tired to shock Peter by swearing. "He had us learning color changing transfiguration by age ten."

James was not to be deterred. "So, will you wear them?"

"I already told you, no!"

"Why don't you just put them on for a minute up here?" Remus suggested. "Try them on, the pull them right off? That might get James off your case."

"Fine," said Peter, irritated. It wasn't fair that James always managed to get his way. "Give me the stupid robes." Even as he put them on, Peter hated that his friends never listened to him, hated that he let them walk all over him.

3.

When James and Sirius figured out that Remus was a werewolf, Peter felt like an idiot. Why hadn't he picked up on the clues? He had just assumed that Remus had a chronic illness, like Mamalydia.

James and Sirius, being, well, James and Sirius, had jumped immediately into finding a solution. So here they were in the third floor passageway.

Again.

James and Sirius were already able to transform with some consistency. It was just Peter who hadn't gotten it. Peter, who would undoubtedly be left behind, because he just couldn't do it. Why couldn't he ever keep up with them? They were supposed to be Gryffindors, not freaking Ravenclaws.

No. That wasn't fair. Ravenclaws would never be attempting something so illegal.

"Come on, Peter, focus," James said.

"If you can't do this, you've no hope of passing your Apparation test next year," Sirius pointed out.

"It's not that complicated. The book says you just have to focus on your core, without letting other thoughts distract you. It's a lot like meditation." James always brought up this part of the book, but it wasn't like it actually helped. Peter could eliminate outside thoughts about as well as he could breathe under water.

He held very still. Breathed in deep. Held the breath, released it, and tried to stop thinking.

And it didn't work. It never worked.

"Wait," said James suddenly. "I've got it." He waved his wand at Peter and said, "Oblivious Temporaria."

It was wonderful, like floating on a cloud, and as Peter's thoughts began to return, he focused on his core.

And something happened. Time seemed to slow, and he could feel himself changing, shifting. And then he was on all fours looking directly at Sirius's shoes.

Now the only problem would be changing back.

James seemed to have realized the same thing. "What do we do if he can't shift back on his own?" James' voice sounded distorted, as if he was trying to speak under water.

"I don't know. Obliviate him again?" Sirius suggested.

James picked Peter up by the tail (and woah, he had a tail, this was by far the weirdest thing he had ever experienced) and held him in front of his face. Peter could only see parts of James' face at a time. First the chin, then the pimple on that James could never quite remove from his nose, and then they were eye to eye. "Does Obliviate even work on rats?"

He was a rat. And wasn't that just telling, that the first time Peter managed really spectacular magic, it was to turn into the most mediocre animal there was?

Sirius got to be a big, playful dog that could hold its own in a fight. James got to be a quick, elegant stag. But Peter? Peter got to be a dirty rat, detesting daylight and living in filth, and really, what did that say about him?

He shifted back easily, and in fact, never had trouble with the transformation again. But it didn't matter.

All he could manage to transform into was a freaking rat.

Maybe he should have just let them go on without him.

4.

"We can't let him do this to Moony," Sirius said, pacing furiously.

"Sirius, what's the big deal," Peter asked. "So what if Snivellous knows? It's not like telling Dumbledore will get Remus kicked out."

"That doesn't matter. What matters is that people won't like it. Not everybody will be as great as Dumbledore is, and next thing you know, there's pressure to expel him, and even if Dumbledore lets him stay, people will act different around him."

"Sirius, Remus can take it," Peter said, flopping onto his bed. "God, where is James? Maybe he can talk some sense into you."

"He's probably hitting up Evans for a date. Wanker. She's never going to go out with him. And who cares if Moony can take it? I don't care if he can take it. I care he's going to get hurt."

"Have you asked him if he thinks you should do this?"

"He'll understand my reasons."

"Don't be so pigheaded," Peter said. "Just because he's clearly in love with you doesn't mean he wants you coddling him."

"He's not in love with me! If you won't help me, fine. I'll do it myself."

Now that was a bad idea if Peter ever heard one. "Why don't you get James to help?"

"I already asked him. He said no, and that I shouldn't do it either."

That stung. Peter hated being the second choice. "Well, maybe you should listen to him."

"Peter, I'm going. Are you going to help me or not?"

Peter went. It was an awful idea, and he never should have done it, but he did.

His job was to get Snape outside.

"Hey, Snivellous!" he called.

Snape turned. "What, Pettigrew? What are you planning to do to me, without your bodyguards to back you up?"

"Nothing." Peter took his hands out of his pockets in surrender. "I just wanted to talk. Where are you headed?"

"Outside," Snape said, looking suspicious.

"Not the library? Don't kid me, Snivellous. I know you haven't written your Charms essay yet."

"So? It's not due until Thursday. Unlike some, I don't need five full days to write a three foot essay. And what difference does it make to you, anyways?"

"Well, shouldn't you get started?" Peter pressed, trying to sound desperate. "You might have to do some research. Let's go to the library. You can help me write mine."

Snape glared. "Why don't you want me to go outside? You're planning something with those stupid friends of yours, aren't you?"

"No, no, of course not," Peter said quickly. "I just thought—"

"That I should study? Pettigrew, you are a dunce. I'm going outside."

Peter really should have gone back to the common room after that, but he was intolerably curious. Why had Sirius wanted Snape to get outside so bad? Peter had only been filled in on the barest details of the plan, and he had no clue what came next. Just that whatever happened would embarrass Snape beyond anything he'd ever experienced before.

So he went outside, and watched as Snape approached Sirius. Watched as Snape pressed the knothole in the tree and started to enter.

Merlin. What was Sirius playing at? Peter knew he should do something, but he couldn't move. Some Gryffindor I am, he thought bitterly. Snape was going to get killed, and he would be accessory to a crime.

And then James was there, pulling Snape away. "You prat!" he yelled. "Do you have a death wish? You knew full well what was in there!"

"And you!" he continued, punching Sirius in the gut. "How could you do that? You almost killed him, you arse!"

"He was going to tell people about Moony! I had to do something!"

"And you decided that killing him was your best option? Or rather, getting Remus to kill him! How do you think that would make him feel? God, Sirius, use your head." James looked furiously from Sirius to Snape. "Whatever, I'm leaving." He stormed off. Later Peter would find out that he'd gone to find Dumbledore, but for now, all Peter knew was that he was leaving.

Peter crept away back to the common room, vowing never to tell James about his part in this.

5.

After Hogwarts, everyone dispersed. James received offers from several Quidditch teams, but declined them all to go into Auror training. At Hogwarts, he had been a Chaser until sixth year. He, Remus, and Sirius had been an unstoppable force. In sixth year, James was made Quidditch captain and made himself the Seeker. Sirius had become a Beater. Only Remus had kept his original position.

Peter had been the commentator.

Sirius, much to everyone's surprise, didn't go into Auror training with James. He explained to his friends privately that enough of his relatives had worked for the Ministry that he didn't trust it. He inherited enough gold from his uncle that he decided to get an apartment and take his time deciding what to do with himself.

Remus was studying for his teacher's certificate. He said that Dumbledore had hinted that he'd make a good teacher, and Dumbledore was the only person he could think of who might hire a werewolf.

Peter had applied for and received a job at Zonko's Jokeshop. His friends were nice about it, but Peter knew they didn't see it as a real job. It didn't matter. Peter's family wasn't rich, and he needed a job that didn't require years of training. It wasn't what Peter had dreamed of doing, (he'd wanted to become a herbologist,) but everyone was putting of their dreams until the war ended.

At nights, he dreamed about mandrakes that didn't scream and Knaliwuffs that cured cancer, and after a while, the dreams felt realer than his life.

6.

"Dumbledore wants all of us to join," James said. "Lily and I have already accepted his offer."

"So that's why you turned down all those Quidditch teams!" Sirius said. "Blimey, mate, we were worried about you. Thought you'd gone 'round the bend." He and Remus were sitting on the same side of the Potters' coffee table. James and Lily were on opposite ends of the table, but every once in a while one of their wedding rings would glint in the light, making Peter feel even more alone. Never mind that everyone thought Lily and James should have waited to get married.

Peter had always had a hard time with dating. At Hogwarts, he had managed to take out Alison Murphy a couple of times, but it had never been very serious. Going to Madame Puddifoot's was all very well, but he had had a hard enough time keeping his grades up. Now all of his friends were paired up, and all he had was a mind numbing job working retail.

"So, he wants us to fight You-Know-Who?" Peter asked shakily. He'd never heard of this Order of the Phoenix before.

"Yeah." James looked thrilled at the thought.

Lily smiled gently "It's not all just about dueling, though. Albus wanted us to fight propaganda, and help strengthen the Ministry. Even if you don't want to be out on the battlefield, there's plenty of jobs worth doing."

Remus spoke slowly. "How will they react to my being a werewolf? I know Professor Dumbledore won't mind, but what about the others? Greyback's on You-Know-Who's side, and a lot of people are convince that all of us feel the same."

Sirius squeezed his hand and said fiercely, "If they won't accept you, they can't have me either." Remus and Sirius had begun dating at the end of seventh year, but Peter still wasn't used to Sirius being so protective.

"I'm sure it will be fine. Albus wouldn't ask you to join if it wasn't okay," Lily pointed out. "We're all fighting Voldemort, and the more people on our side, the better."

Peter flinched. Aside from Dumbledore, who didn't count, Lily was the only person he knew who was brave enough to say You-Know-Who's name.

"Can we have a couple of days to think about this?" Remus asked.

"Of course," Lily said. "Peter, what do you think? Do you want to join?"

All eyes turned to him. Peter didn't know what to do, and it was hard being put on the spot like that. Truth be told, he didn't really want to join, but how could he tell them that? They might not say anything, but he knew that they wouldn't approve of his reason for not joining.

Because his reason was that he was scared, and that wasn't good enough.

"Can I also think about it for a while?"

"Yeah, sure," James said.

Part of Peter thought he would use this time to think of a way to say no, but the rest of him knew that if Remus and Sirius joined, he would too. Like some perverse game of Follow the Leader, Peter went where his friends did, never mind the consequences. Never mind whether or not he wanted to follow.

Never mind whether he thought his friends deserved to be followed.

7.

At the time, it had seemed like his only option. Because Fabian and Gideon Prewett had just died, and their sister Molly had spent the past two weeks in tears. Because when Peter didn't have a mission, which was more often than anyone he knew, he took to visiting people, and visiting Molly made him realize how scared he was. Because, when all was said and done, there was no one in the Order he was willing to die for.

Because Peter wasn't enough of a Gryffindor not to be scared of everything that was happening.

And at the time, it had seemed like a plan worthy of a Ravenclaw. He wasn't important enough in the Order to give You-Know-Who any information of real value. He could play both sides of the field, and if he got any information that would let his side win, he could use it.

And, truth be told, he'd had no idea what he was getting into.

Lucius Malfoy agreed to take him to You-Know-Who (or the Dark Lord, as Peter was supposed to call him now,) and it was scary. And it wasn't fair, because all Peter wanted was to be safe. To stop feeling so scared all the time.

And apparently, you couldn't just walk up to the Dark Lord and offer your service. There were vows involved, and contracts, and Peter left knowing that he couldn't fake his way through the forces of the Death Eaters.

There was no way back from either side.

The Order of the Phoenix involved no vows, but there were other intricacies stopping Peter from leaving. Things like Dumbledore, who still terrified him and would furthermore see through his reason for leaving as if it were Veritaserum. And his friends- oh, would his friends be disappointed in him if he left, and they'd try to still be friends, but without anything keeping them together, they'd grow apart. Peter would be alone, working at Zonko's until the day he died.

It was small consolation to him that he probably wouldn't be able to help either side that much.

8.

"Even Dumbledore won't know," Sirius said, smiling broadly. "It's perfect!"

"Have you told Remus?" Peter asked.

"Sirius's smile dropped slightly. "No. But he'll understand. It's better this way, really. This way I can be in battle without worrying I've put these two in danger. And you've always been…"

"Rubbish at dueling?" Peter supplied.

"That's not what I was going to say. You're rational, Peter. You don't lose you heard whenever you're angry. And you're good at hiding, and you've never liked fighting. Can you see how much sense it makes?"

Meaning you'd just as soon have me out of the way, Peter thought bitterly. I can hide all I want because nobody will miss me. He appealed to Lily. "How will this stay secret? I'll have to give people your address, and then they'll know it's me."

"Padfoot has already given our address to the Order. When we perform the switch, we'll do it so that those people can still get in. If we ever want to invite someone else, you can write the address down and have him pass it along," James explained.

"That's the beauty of it," Sirius said, placing his hands behind his head. "You won't have to keep the secret. Everyone thinks it's me, so you won't have to do a thing."

Lily walked over to Peter and took his hands in hers. "Peter, I know you're scared, but I wouldn't be asking if I didn't know you were capable of doing this."

That was probably the moment Peter should have told them the truth. They would never have forgiving him for his betrayal, but they also wouldn't have died. But Peter still thought that, if it came down to it, he would be able to hide. He never transformed if he could help it, but becoming a rat could save all off their lives in a pinch.

At least, that was what he told himself to help him sleep at night.

Less than a month later, the Dark Lord tortured Peter until he told him everything.

9.

Framing Sirius was probably the worst thing Peter had ever done. For years afterwards, he had nightmares about it, even as a rat. But if he hadn't done it, he would have been attacked from both sides. Both sides thought that he had betrayed them, and nobody liked a traitor.

Peter's other mistakes had all been accidental, happenstance. This time, he knew what he was doing. He knew the exact repercussions for his actions, and still he did it.

That was the first moment when Peter truly felt like a bad guy.

10.

Thirteen years after that fatal night, Peter was a broken man. He lost all of his options that night in the Shrieking Shack. He couldn't stay, so he left.

There was only one thing that could keep him safe at this point. Which was why he was chasing rumors, and not even human rumors at that. Rumors he had heard from stupid rats who would say anything if you offered them the right kind of cheese.

But it was all Peter had to go on.

Lack of food and desire not to be seen had led him to chose traveling as a rat, but it was slow going. He tried to Apparate once, but ended up in Bosnia and didn't try again. He'd only barely passed his Apparation test, and thirteen years as a rat had made it that much harder. But traveling to Albania as a rat took months, and Peter had to constantly remind himself to think like a human.

After weeks of mindless scurrying and eating out of the garbage, Peter decided he needed a break. He had made it to Tirana, covering some amount of land in the process, and it wasn't like anyone would recognize him here. He needed some time with his human brain to figure out what, exactly, he needed to do next. The very thought of bringing his friends' killer back to life repulsed him, but at this point, it was his best option. Maybe once he got some food in him he would think of something else. There was an inn nearby, and he hurried towards it.

There probably were other options, but Peter couldn't think of them. He was scared, and desperate, and at least the traveling had given him a sense of purpose. Now he wasn't sure it was the kind of purpose he wanted to have.

As he reached the door to the inn, a voice called out to him. "Hey! Do I know you?" The speaker's overly cheerful voice grated on Peter's nerve.

"No, I don't believe we've—"

"Yes, we have! You're Peter Petigrew, aren't you? You used to tag along with James Potter and Sirius Black! Only, you're supposed to be dead." The witch scrunched up her face as though trying to solve a particularly hard puzzle.

Peter swore. This was nosy Bertha Jorkins, who had been the biggest gossip in his year at Hogwarts.

Maybe he should have just modified her memory. Hell, maybe he should have just told the truth then and there. Let her take him to Azkaban. But instead, Peter put on his most charming smile and said, "Funny thing, that. How about we go for a walk and I'll tell you all about it."