When a soldier vanishes from Fort Hood, her family do everything they can to bring attention to her disappearance; Secretary of the Army Ryan McCarthy speaks about the investigation and allegations of sexual assault in the military.
When Intelligence follows up on a tip Antonio (Jon Seda) and Halstead (Jesse Lee Soffer) received from a reliable informant about an upcoming drug trade, the team is shocked to discover the mutilated body of a man. Upon further investigation, the body is identified as a government official and when Olinksy (Elias Koteas), Ruzek (Patrick Flueger), Lindsay (Sophia Bush) and Halstead question the man's acquaintances they discover he had access to very important devices. Meanwhile, Burgess (Marina Squerciati) helps plan a surprise for Platt (Amy Morton).
The disappearance of a 20-year-old honors student ends up taking decades to solve.
After a botched undercover job, Ruzek is under scrutiny by the new Street Deputy Crowley (guest star Barbara Eve Harris) who will determine his future with the unit. A suspicious person call turns into a murder investigation when Burgess and her temporary partner Price (guest star Travis A. Knight) discover the body of a dead man in an SUV. After Mouse (guest star Samuel Hunt) identifies the victim as the owner of a security company, the unit soon realizes there might be more to his story. Halstead and Lindsay take a step forward in their relationship.