CHICAGO P.D. Season 4 Episode 5 Photos A War Zone : AFTER THE BODY OF A COLLEGE STUDENT AND A BACKPACK FILLED WITH DEADLY FENTANYL WASH UP IN THE LAKE, INTELLIGENCE IS UNDER PRESSURE TO UNCOVER THE SOURCE OF THE DEADLY DRUG OPERATION. – Intelligence is tasked with tracking down the dealers of fentanyl – a drug that has been linked to multiple overdoses around the city. As they investigate possible sources, the team uncovers a series of dealers in a college smuggling ring. Meanwhile, Tay (guest star Li Jun Li) and Burgess (Marina Squerciati) come across a bloodied child who exposes a dark and twisted secret about his home life with his parents. Additionally, Mouse (guest star Samuel Hunt) causes tension as he looks to reenlist in the army, and Platt (Amy Morton) tells Tay (guest star Li Jun Li) that she has been reassigned to her original post. Also starring Jason Beghe, Jon Seda, Jesse Lee Soffer, Sophia Bush, Patrick Flueger, Elias Koteas, and LaRoyce Hawkins. Guest starring Yuri Sardarov, Nick Gehlfuss and Brendan Dooling.