Police detective Michael Britten (Jason Isaacs) regains consciousness following a car accident involving his wife Hannah (Laura Allen) and his son Rex (Dylan Minnette). Michael moves back and forth between two realities: in one, Rex survived while Hannah is dead; in the other, Hannah survived but Rex did not. Trying to keep both his loved ones alive, Michael starts living a "double life," moving back and forth between the two realities, dealing with different personal conflicts and police partners. He also starts noticing strange links between the two realities.
A mother-and-son team of strange supernatural creatures move to a small town to seek out a young virgin to feed on.