NYPD officer Pete Rennick is shot to death on a rooftop in the dark; Logan and Greevey believe that a crook known as Brutus Walker is responsible for it, and the NYPD initiates a citywide manhunt for him. However, it later turns out that Walker was not the one who shot Rennick; it was his partner, Nicki Sandoval. Investigation reveals that, after displaying many blatant examples of his corruption to his partner, he was afraid that she would report him. So he lured her to the rooftop and tried to kill her, but she killed him first in self-defense. She is cleared of the shooting, but since policy dictates that she should have reported him, she will lose her job.

Detectives arrest three members of the Masucci crime family involved in a fatal assault, which leads to Stone attempting to use the arrest as a means to take down the entire Masucci crime syndicate via charging Mafia chieftain Frank Masucci. However, the plan backfires when Stone discovers that his chief witness (one of the three charged in the fatal assault) perjures himself on the stand, leading to Masucci's acquittal.