Mike Olshansky (David Morse) is an ex-cop turned taxi driver who seeks redemption for a fall from grace by fighting for and righting the wrongs of others. Once a decorated police officer, Mike is abruptly let go from the force after he's caught taking money from a crime scene. Now he must get used to a new life as a cabbie with a boss, Nicolai Zosimov (Mark Margolis), who's always riled up about something, and long days and nights that require a steady supply of caffeine and eye drops.
When one of Mike's passengers is beaten by a group of thugs and another fare asks Mike to help him locate his daughter, he realizes he can still use his police know-how to help those in need. As he contemplates moonlighting as a crime solver, Mike seeks support and assistance from his longtime friends including, Marcellus Washington (Andre Braugher), his former partner who owes his job to Mike since they share a secret that could shatter Marcellus' own police career. Marcellus forever in Mike's debt, gives him inside information that Mike needs to help others, and in return, Mike can go places for Marcellus that a cop just can't go.
Father Tom "Grizz" Grzelak (George Dzundza, Law & Order) is both Mike's drinking buddy and forthright friend. At home, Mike has a lot of issues to resolve with his estranged wife, Heather (Donna Murphy), and son, Michael Jr. (Matthew Borish). The closer he examines his own life, the more he finds himself unable to stop from intervening in the lives that flow in and out of the back of his cab.