I turn my head and I see him, just for a split second and he's gone. I shudder all over when this happens. A smell like mustard fills my nostrils. It's an hallucination, a seizure, some brain damage from the war. Paranoia; I need to get my medications increased.

When I step onto the subway car, his face is watching me from the window into the next car. I run toward the door and he vanishes; the door is locked when I try and open it to follow. The odor is with me and everyone in the subway seems to be watching me.

What if he can move faster than me? Maybe he's running at speeds my mind can't comprehend, so my eyes only perceive his after image. It's not impossible; after the atomic bomb, time started moving backwards and forwards in unpredictable ways. If he was affected by the blast, he could have been accelerated.

I'm going to end up back in the hospital thinking like this. Dr. Zweig will say it's just my guilt talking. He'll say I'm generating fantasy characters to punish myself for having built that bomb.

I get off the subway at my stop and I see him, shadowed in the staircase leading down to the next platform. I shout for him to stop and race after him, but when I get to the stairs, there's no one. I search the platform, then climb the stairs up to the street.

It can't be that he's trying to kill me. Someone who can move as fast as him could snap my neck or push me off a platform in an instant. He could burn down my house and kill my wife and I'd be powerless. No, he wants something from me. Information? My expertise?

I walk to Central Park and take a seat on a bench by the Balto statue. I don't have to wait long. His grinning face flashes in ten different corners of my visual field. I open my hands and gesture to the bench next to me.

After a few minutes of this back and forth, he's seated next to me, light still strobing around him, and his face flickering in black and white. People pass by without noticing, and I wonder if he's visible only to me.

His voice emerges from his mouth, syncopated and high pitched. "Leland Graysmith," he manages to say, "I am accelerated through time because of the weapon you built."

"I'm so sorry," I murmur, "but what can I do? It's done. I'm not going to make any more bombs."

"You don't understand," the man answers. "I'm not here with you only right now. "I'm following you every single instant of your entire life. I will continue my quest until I can kill you before you built that bomb. Soon you will have memories of our meetings throughout your life, before you're erased completely."

"Why haven't you done it already?" I said, shocked, trying to understand his logic.

"It's a chaotic processs, running through time. I overshoot and end up in the distant past or far future all too frequently."

I shake my head, marveling at the thought, as I remember meeting him again, and again, and again. And then, I'm gone.