When NYPD Auxiliary Police Officer Heather Peterson is murdered, the detectives find a diary of her's that details the sexual habits of the police officers at the 15th precinct. These findings cause the detectives to suspect the officers of the 15th precinct had something to do with her death, and the investigation of the cops cause tension between the officers and the detectives.
IAB start interviewing the officers who were in the diary, and Sipowicz and Clark are blamed as rats. A social worker appears to have taken her own life. A former cop wants his ashes buried at the precinct.
Andy and Theo move out. Tony thinks about calling it a day with his ex-wife. Sipowicz and Clark Jr look into the threats made to Clark Sr. A distressed, schizophrenic young man keeps saying "she can't breathe".