After an accident, NYPD detective Sam Tyler inexplicably finds himself back in 1973, where he must help solve a murder that is eerily similar to a case he was investigating in 2008.
As Sam continues to figure out why he is stuck in 1973, he continues to clash with colleagues and superiors over police procedure as they pursue a robbery suspect.
When a decorated Vietnam War vet is beaten to death, Sam's precinct is pushed to the brink to find his killers, but not everyone may be happy with the results they find.
Sam discovers that his mother in 1973 owes money to a gangster who has a very cozy relationship with the precinct. But Sam is the only person who isn't willing to take the payoffs and look the other way.
Sam partners up with his future police mentor in 1973 to find a Puerto Rican man accused of throwing a black girl off the roof of a building--a case that has the black community up in arms and demanding retribution.
Sam helps resolve a hostage situation at the psychiatric ward of a hospital, and the kidnapper's deadline turns out to be the exact same time that the plug is going to be pulled on Sam in 2008.
While investigating a child's kidnapping, Sam discovers some disturbing information about his father, as well as the real reason he disappeared for good on the day of his fourth birthday party.
Hunt gets the precinct in the middle of a turf war with a rival from another precinct in a bank robbery case involving the Russian mob. Meanwhile, a new romantic interest emerges for Sam.
Sam, Ray, and Lt. Hunt are brought in for questioning after Ray's brother, who was involved with the robbery of a notorious Wall Street investor, disappears.
A rock star claims that one of his groupies was abducted by a UFO in the New Jersey wetlands. Meanwhile, Hunt vows to find out whom Sam had sex with in the precinct.
The precinct goes into lockdown when a councilman is shot and killed in the station. But before he is killed, the councilman tells Sam that he is from 2009 and that he has found a way to get back home.
While investigating the murder of a newspaper columnist, Sam crosses paths with a dangerous killer from one of his cases in the future and is convinced that he is guilty of this crime.
Sam goes undercover to bust an Irish mobster, only to cross paths with himself and his mother one more time, as well as his former babysitter, who is the sister of his main target
Irish mobster Jimmy McManus is shot dead after shooting Ray and Chris. The evidence suggests that Sam is the killer, but he insists that he is being framed.