Halstead takes a new recruit under his wing during an investigation. The dynamics are challenging, however, and questions arise over the recruit's complicated past.

When actionable evidence finally surfaces against Sean O'Neal, Upton and the team work relentlessly to build a case in secret. They discover Sean is more elusive and dangerous than anticipated.

Burgess works an extra shift at the 13th District and gets caught in the middle of a drive-by attack on refugees. The team works together to track down the shooter and uncover the true motive behind the attack.

Atwater struggles to find balance as he teams up with a forensic psychologist on an armed robbery case.

Cook turns to her family when Intelligence faces administrative roadblocks that threaten a kidnapping investigation.