I'd had so many plans, just before I went back. I was prepared to an insane degree. I'd spent days camping in the wilderness, gathering enough iron to create a goddamned magnet. I'd memorized the fundamentals of aviation, chemistry, nuclear physics. I knew all there was to know about rebuilding civilization.
And it had all slipped away, one memory after another, fading into a blur, after I'd fallen through the time vortex.
So here I am, trying to explain to some neolithic ignoramus how to make gunpowder. The most I can remember is that it requires a mixture of sulfur,...