The assassination of a seemingly ordinary Brooklyn plumber launches the team into a globe-spanning investigation that ruffles feathers with the CIA. Meanwhile, Tiffany struggles with fieldwork in the aftermath of the Hakim case.

After a series of targeted bombings in Queens, the team fears a citywide gang war is imminent – until a tip from OA's old Army buddy, Clay, directs their attention to an unexpected and powerful foe. Meanwhile, Scola continues to struggle to find a new partner.