Nathan Petrelli could have prevented it all, perhaps, if he'd been alive. If he had been there in Odessa the day everything went so horribly wrong, perhaps he could have made Peter see reason, convinced him, somehow, that Hiro Nakamura and Matt Parkman were telling the truth about Adam Monroe. The words of a brother would have held more weight than the words of two virtual strangers that Adam had convinced Peter were misguided and confused. If Nathan had been there, if he had been more than a ghost that haunted Peter's every step, things that day may have gone differently.

But Nathan Petrelli has been dead for four months by the time Peter rips the door off the vault, and so instead rushing into the vault and making sure the virus's poison was not released into the world, Peter Petrelli merely stands in the hallway beside Matt Parkman's unconscious form and waits.

Hiro Nakamura and Adam Monroe stand before one another, reunited after more than three centuries. Adam looks at Hiro and sees someone who is exactly the same as he had been over three centuries ago: stubbornly determined, idiotically courageous, terribly young. Adam can no longer remember the name of the woman who had been the root cause of their rift, but it doesn't matter. Time has not dulled his resentment for the man who stands before him, nor has it lessened the ache of betrayal he feels within his very soul when he meets those dark, disappointed eyes.

'I should have killed you long ago,' Hiro whispers. His voice is calm and steady, despite the fact that his back is to the wall and the sword he and Adam once shared is merely a breath away from his throat. Sorrow and regret are plainly painted on his features, and Adam feels a hot rush of anger as he sees it. He presses the blade closer to the frantically beating pulse in Hiro's neck and smiles when the time traveler recoils as much as the small space will allow. The desire to make the final, deadly slash is strong enough to make Adam's fingers tighten on the hilt and his stomach quiver with anticipation, but with some effort he manages to keep his hand still. There are still so many lessons for Hiro to learn, and Adam is more than willing to be his teacher.

'We all have our regrets, Carp,' Adam says. Behind his back, he turns the vial over and over in his palm. He meets Hiro's eyes evenly and smiles slightly as he let's the virus fall from his hand. 'I expect you'll have more than most, soon.'

The sound of breaking glass is deceptively soft, but Hiro's eyes widen when he hears it. His hand is slightly raised, and Adam knows that if he had hesitated a moment longer Hiro would have teleported them both away from Odessa. The realization reminds Adam of exactly what Hiro is capable of, and he knows that he must act quickly or Hiro will be lost in the river of time, fighting to go back and correct what had been done.

Unless, of course, he is already contaminated.

Not wanting to take a chance, Adam lashes out before the other man can fully register what is going on. Hiro takes the blow head on, and he falls without a sound to the cold ground. Adam stands over Hiro's still form, and tuts softly in disappointment. Centuries later and Hiro can't take a punch.

There's a noise by the vault door. Adam doesn't bother to turn around; he knows who it is.

'Adam!' Peter exclaimed, sounding horrified. 'What...what happened? The virus, it-'

'It escaped, Peter,' Adam says, making sure to sound properly grief stricken. 'It was an accident. Hiro...he didn't understand. Attacked me. It fell, in the struggle. Not his fault, really. He didn't know.'

'An accident,' Peter repeats incredulously.

Adam nods dismissively, then turns to see Peter staring at him and at Hiro. There is suspicion in his eyes, but Adam has accomplished what he came for and no longer really cares if Peter believes him anymore or not. He watches patiently as the empath looks from him to Hiro to the relatively harmless looking broken glass on the floor and wonders if Peter is expecting the earth to shake or the skies to fall.

'How long do we have until it spreads?' Peter asks finally. His voice is hoarse and he does not meet Adam's eyes. 'I could go back; Hiro could go back and fix this.'

Adam only shakes his head sadly. 'I'm afraid it's too late for that now. You're already contaminated. Even if you're immune to it, you will spread it no matter where, or when, you go. The only thing we can do now, Peter, is warn people the best that we can.'

It isn't a lie, exactly. It may even be the complete truth. Adam doesn't know for sure, but he speaks with enough certainty to convince Peter, at least for the time being. Peter swallows heavily and meets Adam's eyes.

'What do we have to do?'

Darkness tugs at Hiro relentlessly. He struggles furiously to throw it off, but without fail it pulls him down again and again, leaving him only distantly aware of what's going on around him. His head aches dully and voices he barely recognizes mutter around him, echoing strangely and making it impossible to determine where they're coming from. A noise, loud and terrible like the blaring horn of a train, explodes suddenly into the darkness. The dull pain in Hiro's head suddenly becomes sharp, nearly unbearable. He tries to turn, tries to get away from whatever is making that horrible sound, but the darkness is too thick and cloying and all he manages is a small groan. The noise grows louder and louder, until Hiro can't stand it anymore. He gives up his struggle for consciousness and is almost grateful when oblivion eagerly swallows him up.

When he finally wakes an indeterminable amount of time later the noise is gone and his mind is a bit clearer, though the place where Adam struck him still throbs painfully. Something hard and unyielding presses against his back, and the muscles in his arms burn uncomfortably from being in one position for too long. Wincing, Hiro tries to shift and immediately feels something cold and metallic bite into his wrists. Startled, he freezes, waits a moment, and then tries again, this time pulling hard on the restraints in an effort to tug free of them. He succeeds only in making the pain in his arms grow worse.

Already exhausted from his efforts, Hiro lets his arms relax against the back of the chair. Swallowing nervously, he orders himself not to panic and attempts to slowly open his eyes. It takes him three tries before he manages it, and when he finally is able to look around all he can see are bare concrete walls and, in one corner, a flat slab that might in some depressing world pass as a cot. He can't see a door, but he has no intention of sticking around long enough to find out where it is. Determined to put as much distance as possible between himself and this cold prison, he closes his eyes firmly and concentrates.

Nothing happens.

'Kensei,' Hiro mutters, feeling his heart seize up. 'What have you done?'

Ando drums his fingers nervously on Hiro's desk and looks at the clock for what feels like the millionth time. Hiro has been gone for hours and hours, but Ando swears to himself that he isn't worried. There are dozens of perfectly acceptable explanations for why Hiro hasn't come back. There is no reason to think that Hiro is lost, or stuck in time, or bleeding in an alleyway, or shot, or sick, or-

Ando's cell phone rings suddenly, loud and startling in the otherwise quiet office. With a cry Ando dives for it, his fingers fumbling over half a dozen stupid items that he is positive weren't there a moment ago. Finally his hand closes over the phone and, breathlessly, he answers.

It isn't Hiro on the other end, and Ando feels his blood run cold as he listens to what the unfamiliar voice has to tell him.

The facility is eerily empty and as he wanders the deserted hallways Peter wonders how many of the missing workers fled without knowing they were carrying a deadly disease. Matt Parkman has vanished, presumably gone back to wherever it was he came from, but Peter barely spares him a thought. There is a voice in his head that doesn't come from any telepath, a voice that haunts him relentlessly, never letting him for a moment forget the mistakes that led him to this point. It is the voice of guilt, Peter thinks, but it sounds remarkably like Nathan Petrelli.

In the days that follow that quiet voice becomes deafening.