Joey Harker is just an average teenage boy, worrying about grades and getting the girl he has a crush on. In fact, the only thing notable about Joey is his terrible sense of direction. So when he gets lost on a field trip, he gets really lost. He travels from his reality into an alternate one. Little differences between the worlds quickly begin to add up, and soon he’s being pursued by sinister forces—including an older boy who looks suspiciously like him.

It all seems to defy belief, but Joey ultimately can’t deny that the circumstances he faces are real. With the help of Jay, the alternate version of himself, he makes it to InterWorld headquarters—where everyone looks like him, except for deviations like age, fur, and even wings. The fate of the world may rest on average, everyday Joey’s shoulders, it seems. Make that the fate of many, many Joeys, and many, many worlds.

Gaiman and Reaves take readers on a journey across a universe (or rather, an Altiverse) torn between magic and science.