Season 1

Serving on the arson squad, Shannon attempts to gather information from an old adversary who is now running a protection racket.

Detective Jack Shannon returns to New York City to investigate why a seemingly airtight case has disintegrated. This marks Jack's first case back in the Big Apple. He must defend himself against accusations that, as a New York police officer, he coerced a witness. However, his progress is halted when the NYPD scrutinizes his conduct in his most recent case.

Shannon discovers that his father-in-law, Paul, is a victim of loan sharks. Paul has been pressured to commit a crime in order to repay a debt. While Shannon is occupied with helping his young son adjust to their new life, he learns that his father-in-law, a fisherman, is in desperate need of assistance. The loan sharks are threatening to take Paul's boat and home unless he allows them to use his boat for drug smuggling.

Ivy Horton attempts to kill her ex-husband, Alex, a mental patient, to protect herself and her daughter. The man who threatens his family cannot be arrested until he commits a crime.

Shannon teams up with a female detective investigating a series of rape cases. However, the policewoman is resentful of his assistance.

Shannon is involved in corruption, but his true objective is to dismantle a gambling operation. This all began with the suicide of a police officer who was suspected of accepting bribes. Seeing an opportunity, Shannon decides to build relationships with some of the influential people in town. One notable figure is Burt Harvey, who is eager to make an "investment" in exchange for valuable information. With the assistance of Connie, the girlfriend of the deceased officer, Shannon and Moraga set out to eliminate all illegal activities.

Shannon's childhood friend and adult rival, Bunky James (played by Ron O'Neal), is released from prison to assist him in investigating the murder of a politician, which appears to be an execution carried out by terrorists. Shannon delves into the group suspected of being responsible for the assassination of the black politician. However, the investigation is further complicated by the involvement of organized crime.

Norm White's personal problems nearly jeopardize the admirable work done by his partner, Shannon, and the other officers in tracking down a band of skilled bank robbers. Norm struggles to perform his duties effectively because he is conflicted about allowing his wife, Patty, to take a job to help make ends meet.

Shannon works undercover in a mission to catch a killer. After a series of obscene phone calls ends with murder, Shannon offers protection to an actress who may be the next victim.

Shannon is investigating a violent robbery that his young son, John, witnessed. While walking home from school, John sees a robbery during which a policeman is shot. His fear for his father's safety grows when Shannon is assigned to track down the dangerous killer.