Detective Britten suddenly becomes a suspect in his own case when an FBI agent, Santoro, questions his methods of tracking down a serial killer thought to be dead. Meanwhile, in the wake of her son's death, Hannah is finding comfort in exploring the possibility of moving to Oregon and going back to school.

While investigating an alleged suicide during an upscale yacht party with Detective Vega, Detective Britten runs into Rex's former babysitter Kate. Later, in a case Britten is investigating with Bird, Kate appears again, this time as a suspect. Dr. Lee and Dr. Evans try to help him make sense of his run in with these two very different versions of the same woman.

Rex is kidnapped by an escaped convict Michael arrested 10 years ago; an investigation in Michael's other reality gets in the way of an event honoring his deceased son; clues from both realities lead to Michael's sanity being questioned.

Detective Michael Britten continues to deal with his parallel versions of reality. In one world he's looking for ways to reconnect with his son, Rex, by offering him some normalcy while they deal with his mother's death. In the other, Britten works to understand the emotions that his grieving wife, Hannah is going through. Meanwhile, a witness in the murder of a homeless man tells Britten and his rookie partner, Vega that a "small guy" was spotted at the scene of the crime. When that clue crosses over into the case Britten is working on in his other reality, Bird, is confused by his partner's sudden interest in the height of the suspects they are investigating. Meanwhile, Britten's captain, shows growing concern over his behavior. Later, the events surrounding the fateful accident that changed Britten's life come into question and throughout, Dr. Lee and Dr. Evans continue to present their dueling theories on Britton's condition.

When Detective Michael Britten regains consciousness following his family's car accident, he is told that his wife Hannah perished, but that his teen son, Rex, has survived. As he tries to put the pieces of his life back together he awakens again in a world in which his wife is very much alive, but his son Rex died in the accident. In order to keep both of his loved ones alive he begins living two dueling realities. Trying to regain some normalcy Michael turns to his work solving crimes in both worlds with the help of two different partners, Detective Isaiah "Bird" Freeman and Detective Efrem Vega. He begins to solve impossible cases by using his dueling realities to gain unique perspectives and link clues that cross over from world to world. Helping Michael to navigate his new existence are his bureau assigned therapists Dr. Evans and Dr. Lee..