It all started with a newspaper clipping.

I would've never dreamed that such an ordinary interaction would lead me, a man with nothing left but a few shreds of sanity, to attempt what everyone claims to be impossible. But that life-changing instant is now ingrained in my mind, replaying over and over as I plot my escape.

It's the moment that I remembered what it feels like to have a purpose.

This morning, the Minister of Magic, Cornelius Fudge, was performing one of his monthly inspections of Azkaban. Spending any amount of time in the most terrifying high-security wizard prison is dehumanizing, to say the least, and I've spent twelve years or so here, so I've always done my best to strike up a conversation with anyone who passes by my cell. I've even tried talking to the Dementors a few times, more out of frustration and boredom than anything else. As it turns out, soulless materializations of misery aren't great conversationalists – and most of the humans here aren't much better. I suppose nobody wants to linger around an accused mass murderer long enough for a decent chat. But Fudge, as inelegant and spluttering as he is, always pauses when he reaches me.

I assume it's because I'm more interesting than the many prisoners who huddle at the back of their cells like empty husks, or the rarer ones (like my cousin Bellatrix) who hiss or scream bloody murder as people go by.

Admittedly, during the first few months of my wrongful imprisonment, I wasn't quite as composed. But over time and under the influence of the Dementors, my anger, desperation, and despair morphed into a quiet, lonely acceptance. I gave up the hope of returning to my life as it had been before Voldemort's downfall, because I don't have much to return to. Most of my closest friends are dead, and those that are still alive believe me to be the killer. As cruel as it is, I came to view this imprisonment as my fate. Still, I never forgot my innocence, and I vowed not to lose my mind as so many others do here - even if lapsing into madness would've been a relief in some ways.

So, as two of the few sane people here, the Minister of Magic and I developed a monthly habit of distracting each other from this living hell.

Judging by the queasy expression that the portly man always wears as he strolls down the prison's cold, damp corridors, Fudge hates having to venture into Azkaban almost as much as I hate being trapped here. But for some reason, his discomfort would morph into curiosity whenever he saw me. Usually, I would call out to him with a dry joke, and he would hesitate with an exasperated half-smile, like he knew he shouldn't be playing along. But he never could resist the interruption to his miserable inspection – a routine which I somehow weaseled myself into.

Our conversations would only ever last a few minutes. At my implicit request, Fudge would update me on current events – mostly trivial things. Sometimes, if he was in a bad mood, he would complain about personal matters, like pointless arguments with his wife or troubles with some Ministry employee who went off the rails. (I suppose I was the perfect confidant for all that – it wasn't like I was going anywhere or gossiping to anyone else.) Then I would come up with some clever response – I've even made him laugh a few times – and ask him for the copy of the Daily Prophet that he always seemed to have in his cloak. Before Voldemort fell, I never used to care about reading the news or solving the crosswords – but in this tiny, empty cell, I would take whatever recreational activities I could get.

Little did I know, one of those short interactions would force me to rethink everything that I thought I knew.

As Fudge's footsteps fade down the corridor, I recline against the wall and shake out the newspaper to the front page. Gazing back at me is a black-and-white image of a grinning family who won a handful of Galleons. I scan over each of the Weasleys with vague interest, imagining their heads of flaming red hair. (I don't know much about the Weasleys, but I do know a bit about the Prewetts. Molly's younger brothers, Gideon and Fabian, were in their last year at Hogwarts when I started – and they were in the Order of the Phoenix with me, before they were killed by Death Eaters.) I almost smirk when I notice a pair of identical twins whose mischievous grins remind me of their uncles.

Then I glance at the taller boy next to the twins, and I freeze.

No. That can't be...

With shaking hands, I bring the paper closer to my face. My eyes are fixed on the rat perched on the boy's shoulder. My heart is pounding painfully hard. I haven't felt this tense in years.

Calm down, I tell myself uneasily. This place is getting to you – it's making you imagine things. That traitor blew himself up twelve years ago. It's just a rat.

I continue to stare.

Just a rat, I repeat to myself, willing my eyes to close or focus on something else.

I can't. My eyes dissect the image like my life depends on it. All the blood is gone from my face. I'm not even sure if I remember to breathe.

Just a rat with the same coarse gray-brown fur, the same long tail, the same scar on his left ear from the time Moony nearly crushed him, the same beady eyes in an unusually light shade, and—

My stomach feels like it's sinking through the floor.

–and a toe missing.

The sight wrenches my mind into the past with such force that I feel lightheaded.

It was the day after that Halloween - the day after my life fell apart. Voldemort was gone, my best friend was dead, and I had only one objective. I was hurrying past Muggles down a crowded street, focusing intensely on the tracking spell I was using, when I spotted a familiar head of brown hair. Thoughts of murder blazed like fire through my veins. Peter glanced over his shoulder, and our eyes met. I saw the terror flood his face, and I felt a surge of cruel satisfaction.

Immediately, I raised my wand.

At the moment, I didn't care about the consequences of dueling on a crowded street. The back-stabbing coward in front me was the reason James and Lily were gone. Not only that, but he'd also been leaking information to the Dark Side for over a year, causing countless more deaths of Order members. And I'd considered him one of my best friends. I couldn't have cared less what happened after this. All I knew was that I wanted him dead.

Before I could get a clear shot, the fear in his eyes turned to rage, and he yelled, "Lily and James, Sirius! How could you?"

Some of the Muggles around us parted, looking bewildered. I had an opening now. But, for the briefest moment, I hesitated. I was shocked that he had the nerve to accuse me of the crime he'd committed. A little voice in my head chimed in nastily: You did tell them to use him as their Secret Keeper instead of you. If you hadn't done that, they'd still be alive.

I never would've done that if I'd known what he was! I silenced the voice, feeling shaken all the same.

That hesitation was my downfall.

Suddenly, a blinding light engulfed my target, tearing through the air with a sound like a jet engine. I managed to deploy a Shield Charm before the powerful ripple of force reached me. When I released my charm, I was standing, a bit deafened but unscathed, on a three-foot-wide circle of asphalt amid the massive crater that Peter's spell had created. Water spewed from pipes that had been unearthed and cleaved straight through. Muggles screamed and ran. A dozen or so people were lying motionless on the decimated sidewalk. And Peter was nowhere to be seen.

Hardly processing any of it, I walked to the center of the crater, staring numbly at the spatter of blood where my ex-friend had been. My insides twisted when I spotted a bloodied finger lying in the dirt.

A cruel, involuntary, humorless laughter rose from the pit of my stomach. I couldn't help but feel relieved – in a horrible, exhausted sort of way. Peter Pettigrew was a murderer, a spy, and a traitor. He deserved nothing better than to be blown to smithereens by his own reckless spellwork. I saw it as poetic justice that he would meet death right after his master was defeated – on his information, by his betrayal of his so-called friends.

That's why I hardly even cared when the Ministry officials showed up and accused me of murder. It's what I'd been trying to do anyway. I only felt bad that I didn't act sooner; maybe I could've spared all those Muggle bystanders if I'd just gotten on with it. But I would've accepted a prison sentence if it meant avenging my friends.

And I did accept it, eventually.

But if Peter is alive...

The sound of my shuddering breaths brings me back to the present. The rat in this picture looks just like Peter's Animagus form – and it's missing a toe. My brain starts working in overdrive. Could he have faked his own death? The explosion did reach the sewers. He could've cut off his finger and bolted. And it makes sense that he would masquerade as someone's pet; that's as cushy of a life as a rat can get.

I grit my teeth as rage ripples through me. Twelve years. He's been out there for twelve damn years, living as someone's bloody pet, comfortable and cared for, while I've been in here rotting for the crime he committed!

My anger trickles into unease as I continue to stare at the photo. What's his end goal? Why stay in hiding as a rat when he could just use an appearance-altering charm and start over? And why the Weasleys?

The answer hits me like a punch to the chest. "Harry," I mutter, resisting a visceral urge to tear the paper to shreds. The boy with the rat on his shoulder, Ron, looks to be the same age as James and Lily's son, Harry, which means that they are probably attending Hogwarts together. They could even be sharing a dormitory for all I know. If Voldemort ever regains power, then Peter would be in the perfect position to strike on the boy who ended the war and (almost) ruined his run as a spy.

The boy who was orphaned at the age of one, thanks to him.

The boy who also happens to be my godson, and I haven't had a chance to truly know him, also thanks to that rat.

The boy who is almost a teenager now, though I can only picture him as a toddler with big green eyes and a spiky mop of black hair, giggling uncontrollably as he zooms around on a toy broom.

That shameless, self-centered bastard!

I'm so enraged that I feel like I'm going to be sick. Trembling, I find the date on the paper. It's nearing the end of July. In a little over a month, the murderer who brought about James and Lily's deaths would be staying, undetected, in the same castle as their son. In fact, he's probably already been doing that for two whole school years, waiting for an opportunity to finish what he started and reap the rewards for his faithfulness to Voldemort.

And I'm the only one who knows.

A crushing sense of responsibility suddenly weighs on my chest. I was never able to forget the fact that I'm part of the reason that the Potters were killed in the first place. They might never have died if I hadn't convinced them to change their minds. I was supposed to be their Secret Keeper, not Peter. And they had to pay the ultimate price when my plan backfired. Worse yet, I set out to avenge them, and I failed. Their murderer was still alive and in hiding, without retribution or remorse, fully prepared to kill their son, the boy whose life he'd already damaged beyond repair.

Past the guilt and fury warring within me, I feel something fiery and white-hot unfurling in my core. My stomach squirms as I recognize the long-lost sensation: Drive.

I have a reason to be alive again. I have a goal – a purpose.

I would much rather die than let that rat touch a hair on my godson's head. I need to stop him before he causes any more tragedies. And there is no way to accomplish that from a grimy prison cell.

So, I suppose I'll have to leave.

Unfortunately, there are many unknowns in this situation, so I suspect that any plan I come up with will be full of holes. I don't let that worry me much, though. I have always been the type to figure things out as I go. There is one thing I know for sure: I may have managed to keep my sanity this long, but I would go mad knowing that all of my suffering was for nothing. I can't afford to waste away here any longer, for my own sake and for Harry's.

I call to mind that frightened look on Peter's face the day I cornered him, and the fire of determination in me burns even hotter.

It's time for me to finish what I started.