The series tells the story of New York City police detective Sam Tyler (played by Jason O'Mara), who, after being struck by a car in 2008, regains consciousness in 1973. Fringing between multiple genres, including thriller, science fiction and police procedural, the series remained ambiguous regarding its central plot, with the character himself unsure about his situation. The series also starred Harvey Keitel, Jonathan Murphy, Michael Imperioli, and Gretchen Mol.