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.

Five Ecuadorians are found murdered at a small nightclub in an apparent robbery gone bad. Sipowicz, Simone, and Martinez work on the case where a tip from a waiter at the club leads them to try to find the two killers responsible. Meanwhile, Simone begins his undercover work for the FBI when he secretly meets with Joey Salvo who wants Simone to run a license plate number for him. Also, Russell and Medavoy are looking into a suspect in a spouse abuse case where Medavoy's commitment to Abby and Kathy hampers the investigation due to Medavoy's emotional attitude. Also, Medavoy discovers that Detective Gotelli is stealing money out of his locker in the light of his medical condition.