But innovation is never as neat as any of us would like. He can only travel back a set number of years, way before his daughter is born.
So before he goes back, he does his homework. He researches. He spends hours in the archives of war museums, flipping through files, searching for someone new.
Searching for you.
And then he makes the leap, jumps back a few decades, emerges the same if a little nauseous for a spell, into a world transformed. The colours seem brighter here, the smiles wider, flashing ferociously, the eyes emptier and hungrier.
But of course, that's what he would see. He, an interloper. Here, a brave old world.
On his third day back, he finds you, speaks to you. He asks you for the time. His hands are trembling; his eyes never leave yours. Do you remember? It was a year or so ago.
Your paths keep crossing, but he gets more cautious, becomes a flickering shadow, in and out of the corners of your life. Waiting. Watching.
