Simone and Sipowicz search for a killer of a bookie in which Mike Roberts returns to offer his help. Meanwhile, Donna returns from her long vacation trip to resume her position at the station and her temp, John Irvin, gives everyone farewell greeting cards when he is moved to the anti-crime lab upstairs. But Donna continues to treat Medavoy with resentment which leads to him thinking that she might be finished with him. Simone's obsessive witness, Joyce Novak, goes too far when Simone rejects her advances after he tells her that she will not testify in the upcoming trial. This leads to Joyce attempting to murder Diane Russell when she correctly assumes that she and Simone are romantically involved. Sipowicz and Sylvia meet with the priest to help with their wedding and later she hears a story about what has contributed to Sipowicz's loss of faith.

Sylvia confronts Sipowicz about her suspicions that he is going to late-night bars and drinking again, and the effect is everywhere. Lt. Fancy is forced to sent him home after Sipowicz walks in one morning drunk. Sipowicz even fights with some street punks, gets beaten up, and Simone offers to look for the men that beat Sipowicz up. Meanwhile, a new administrative assistant, named Lucy, arrives as Donna's replacement. Also, Russell investigates a young woman, named Angela, who claims to have been stabbed by her jealous boyfriend. Simone, following a lead from a streetwalker named Deena, finally tracks down and confronts the two thugs who murdered Andy Jr. and guns them both down in a hail of bullets.

Sipowicz meets with a priest to talk about his troubles and finally sees the light. Afterwards, he, Simone, and Russell work together to investigate a robbery where an auto mechanic got shot to death. Following the apprehension of a wounded suspect, the detectives also arrest the suspect's younger brother who is unwilling to make a statement against his brother out of blind loyalty. Meanwhile, Medavoy works on finding a new place to live while he, Martinez and Lesniak work on finding the suspect of a drug-related double murder. John Irvin passes out farewell notices to the employees when he announces that he is moving back to the 1st Precinct uptown. Simone and Russell plan a trip to the beach. Medavoy meets Anne McGuire, a new detective, while working on his case. Elsewhere, Lucy is disruptive at work and Fancy tries to find a way to transfer her out of the building. Baby Theo gets baptized which seems to bring Sipowitz and Sylvia back together.