Danny and his nephew Joe Hill investigate the homicide of a delivery driver who may have been connected to an illegal narcotics ring in the city. Also, Eddie is determined to save the job of a probationary police officer who may be fired for responding to a crime; Frank faces a hard decision when he discovers Gormley is non-compliant with NYPD residency requirements; and Erin clashes with her boss, D.A. Crawford, when a seemingly rehabilated criminal from an old case becomes the subject of an armed robbery investigation.