Mickey O'Sullivan

Halstead's life is put in danger when the surviving Bembenek brother hires an assassin to avenge his dead sibling, Jacob.

Atwater goes under cover to take down a gun trafficking ring but discovers an officer from his past is under cover in the same organisation.

After a video is posted online showing the beating and murder of a man burnt alive, Intelligence tracks down a group of vigilantes torturing and killing sex offenders.