Two escaped murderers are pursued by the squad and two visiting detectives from Chicago.
A Chicago crime resembles a decade-old New York City case, so police from Chicago arrive and team up with the squad to track down a suspect they had to release earlier.
Lindsay calls on Voight and his unit for help with her first case on the federal task force; Burgess is relegated to desk duty.
A hit man tries to take out Halstead but accidentally shoots a bartender instead. Meanwhile, Olinksy asks Bembenek to cancel the hit; Voight and his team go after the hired assassin; and Platt and Nadia come to an understanding.moreless
Lindsay is at a crossroads regarding Charlie and Halstead convinces her to talk to Voight; Burgess copes with losing her shot in joining the Intelligence Unit; Voight discovers Jin is a Internal Affairs mole; The Intelligence Unit investigates stolen explosives at the construction site; and the team loses one of their own.moreless
The Intelligence Unit investigate a violent armed robbery in a bank; Burgess asks to go undercover on the case to prove herself; Platt asks Ruzek for an unusual favor off-the-books; and Halstead spends time with the family of his high-school sweetheart.moreless
Voight works with a former partner during an investigation, and he's also assigned a new Internal Affairs handler who doesn't trust him. Meanwhile, Halstead seeks help gathering information about Lonnie Rodiger; and Olinsky attempts to deflate Ruzek's ego and offers a boost to Atwater.moreless
As the squad investigates the brutal and mysterious stabbing death of a musician, they find out the victim had something to hide. After more than a year, Frank Sr. returns with some shocking news.moreless
This time around the intelligence unit goes after a counterfeiting operation that could mess up and ruin things for the state. Meanwhile, Atwater and Burgess are sent after a hoarder to make her clean up or put her in jail and find something they didn't expect. Olinsky tries everything to protect his daughter and Voight has a decision to make regarding his son, who was recently released from prison.moreless
A severe car crash involving an entire family results in an all-hands-on situation in the ER, as the eldest daughter is left to make the toughest decision of her life. Meanwhile Teddy, still in the dark about Henry's death, calls upon Cristina to help with her patient in the O.R., and Lexie finds herself working alongside Mark's new girlfriend, Julia, during an eye surgery.moreless