"I'm afraid trying to kill you was a mistake. Angus is determined to go on with his invention anyway. But if I can convince you not to take his proposition, perhaps I'll be able to destroy his time machine before he has time to hire another guard."
"But why do you want to destroy it?"
"Because I'm trapped here in your primitive age. Because I'll never get back to my own time, that's why."
"I don't get you."
"Look. My ancestor Angus Haney invents a time machine. It can travel forward in time, but not back. In my own day I invent a machine based to a large extent on Angus' earlier machine. It can travel back in time, but not forward. I come here, visiting your mid-twentieth century, thinking I can return to my own day in Angus' machine."
"Then why don't you want it built?"
"Because Angus explained to me that I was wrong. The machines are slightly different. I can travel on my own, but not his. He can travel on his own, but not mine. Result, I'm trapped here. Unless—"
"Unless what?"
"Unless I can prevent Angus from completing his machine. If it's destroyed, my own machine would have been impossible because, as I have said, most of my work is based on Angus'. You'll help me?"
"No," I said. "Why should I?"