Burgess and Atwater come across a gunshot victim and the only witness is Olinsky's daughter; Ruzek goes to Burgess for help with an undercover mission.
Platt and Voight discuss their pasts; Jin uses a scapegoat when he is caught tinkering with Voight's computer; Lindsay realizes she needs to come clean.
Intelligence searches for a missing teen who they believe poses a threat to students at his school; Atwater wants to make a good impression on a police captain.
Following a big heroin bust, Olinsky learns that the suspects are holding his wife hostage; Burgess and Roman get an assignment that pairs them with a K-9 officer: Roman's former partner (Spencer Grammer).
A case involving one of Chicago's most wanted fugitives hits close to home with Olinsky; an altercation with another officer lands Sean Roman in hot water; Platt helps Nadia prepare for her polygraph test.
