Two events made September 1 a memorable day for Jesse Cullum. First, he lost a pair of Oakley sunglasses. Second, he saved the life of President Ulysses S. Grant.
It's the near future, and the technology exists to open doorways into the past—but not our past, not exactly. Each "past" is effectively an alternative world, identical to ours but only up to the date on which we access it. And a given "past" can be reached only once. After a passageway is open, it's the only road to that particular past; once closed, it can't be reopened.
A passageway has been opened to a version of late nineteenth century Ohio. It's been in operation for most of a decade and it's no secret, on either side of time. A small city has grown up around it to entertain visitors from our time, and many locals earn a good living catering to them. But like all such operations, it has a shelf life; as the "natives" become more sophisticated, their version of the "past" grows less attractive as a destination.
Jesse Cullum is a native. And he knows the passageway will be closing soon. He's fallen in love with a woman from our time, and he means to follow her back—no matter whose secrets he has to expose in order to do it.