Forced to cease operations while under investigation by Internal Affairs, Intelligence goes off-book to bring down Reid once and for all. Ruzek and Burgess consider delaying their nuptials.

The showdown with Deputy Chief Reid intensifies when Intelligence narrows in on Otero.

Ruzek witnesses a tragic accident on an icy bridge, leading Intelligence into a dark, sinister case involving sex trafficking.

Cook works with a confidential informant for the first time in a robbery-murder case with links to a star college athlete.

Voight and Chapman work together to uncover Deputy Chief Reid's shadow dealings as Reid assigns Intelligence to a carjacking case.

The search for the suspect in a shooting uncovers a surprising personal connection to Atwater and Val, raising questions about their relationship status.