Jason Dessen is walking home through the chilly Chicago streets one night, looking forward to a quiet evening in front of the fireplace with his wife, Daniela, and their son, Charlie—when his reality shatters.

It starts with a man in a mask kidnapping him at gunpoint, for reasons Jason can’t begin to fathom—what would anyone want with an ordinary physics professor?—and grows even more terrifying from there, as Jason’s abductor injects him with some unknown drug and watches while he loses consciousness.

When Jason awakes, he’s in a lab, strapped to a gurney—and a man he’s never seen before is cheerily telling him “welcome back!”

Jason soon learns that in this world he’s woken up to, his house is not his house. His wife is not his wife. His son was never born.
And someone is hunting him.