Cal Donley wakes up missing his recent memory and covered with blood. Someone else's blood. He learns that he's a computer engineer living on the L5 orbital colony Daedalus, and he's married to a tantalizing stranger. Worn on his wrist is Vincent, a watch-sized artificial intelligence who can also tell time. But Vincent is missing some of his memory, too. As Cal tries to find out what happened during his long blackout, and in particular what happened in the last few hours of the gap, people around him begin to have accidents. Fatal accidents. Pretty soon, Cal knows only one thing for certain. What he doesn't know can kill him.