In the wake of the World Trade Center disaster and Danny's disappearance, the 15th Precinct faces a gruesome investigation when four young girls are found dead in an apartment. Sipowicz, in a black mood because his partner's whereabouts are still unknown, takes out his anger on everyone around him. While investigating the murders, Sipowicz and McDowell team up with a young narcotics officer, John Clark. When a possible lead in Danny's disappearance emerges, the trail leads right to the son of a Mafia capo. When the worst possible news is confirmed, a witness is enlisted to wear a wire as they go after the suspect. As Medavoy, Jones and McDowell learn the quadruple murder was a robbery gone bad, Sipowicz once again confronts the temptations from the past, anticipating the next day's undercover operation.