The team fervently investigates the murder of a P.D. informant, and they discover something shocking; Voight and Ruzek brainstorm ways to help Burgess.
One of Halstead's former Army colleagues is connected to a deadly blast; the FBI begins to investigate Roy's disappearance; Upton is tense about her secret.
An incident at a bowling alley and a problematic home renovation require the first responders' attention; Bobby and Michael go on a camping trip with Harry.
Fin investigates a case involving a sexually assaulted Army Ranger, but he finds it hard to uncover the truth as the victim refuses to offer any information.
When a responsible 15-year-old girl vanishes, a desperate search to find her leads investigators toward a little-known youth hangout at a hidden creek.
A break in the case of a missing teenager comes from a chilling message scrawled in the dirt of a local teenager hangout when authorities investigate the area.