The 8th precinct is distraught when one of their detectives from the anti-crime unit is found murdered. Carl Desmond was shot in the head and his body was thrown in a dumpster. His colleagues and grieving widow, Mary Beth suspects that his murder was an act of revenge by someone he had previously put away. Karen is put in charge of the case, as she and the rest of the detectives must tread carefully in the investigation into the murder of one of their own.

When Mary Beth's past infidelities come to light, Tom and Marty investigate a married man named Don Bellamy whom she was having an affair with. While going in a different direction, Karen and Jim put their reputation on line with other cops at their squad when their main suspect is Carl's partner, Eric who had put in a request for a transfer a week before the murder. In the midst of the investigation, a frustrated Jim confronts Marty who is purposely making things difficult for him by rearranging the squad so that he would walk and bang into the office furniture.