Melissa Carlson

Olinsky's daughter is severely hurt in a massive warehouse fire; Voight investigates the fire's potential origins, connections between the building's owner and potential arson suspects.

Halstead and Atwater go undercover in a bid to prevent military grade weapons from hitting the street; Voight calls in a favour in order to clear Olinsky's name.

Platt and Voight reflect on their pasts; Jin looks for a scapegoat when he is caught with Voight's computer; Lindsay realises the time has come to come clean.

Having survived a car bomb attack that nearly killed him and his family, Hank uses any means necessary to get his hands on the man he holds responsible, a drug dealer recently released from prison.

A member of the team is taken hostage by a father who demands Intelligence locates his daughter, who he suspects has been kidnapped.

A case involving one of Chicago's most wanted fugitives takes a personal turn for Olinsky; Sean Roman is in trouble after an altercation with another officer; Platt helps Nadia prepare for a polygraph test.