AFTER DISCOVERY OF LARGE AMOUNTS OF ‘COP KILLER’ AMMO, THE INTELLIGENCE UNIT IS IN A QUEST TO FIND THE SOURCE – Voight (Jason Beghe) and team head to a house that’s been associated with a number of top gangs. Events at the search result in Ruzek (Patrick Flueger), being encouraged to seek some counseling which may have lasting repercussions professionally and personally. Meanwhile Halstead’s (Jesse Lee Soffer) temper rises when he comes in contact with some unwelcomed people from his past. Jon Seda, Sophia Bush, Elias Koteas, LaRoyce Hawkins, Marina Squerciati, and Archie Kao also star. Robin Weingert, America Olivo, Amy Morton and Josh Segarra guest star.