The team is on the case when a suburban couple is murdered and all forensic evidence points to the home's previous owner, who is currently serving 10 years in federal prison.
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.
When the sister of Sydney Ortiz is the victim of an attempted kidnapping and sexual assault, Sydney seeks help from Isobel and the team in tracking down a meticulous serial offender who leaves no evidence behind.
When a chaotic campus protest turns deadly, the team is called in to help quell the mayhem and track down the murderer. Meanwhile, Jubal is concerned when Tyler is detained along with a group of student protestors.
The team is called in to track down a serial killer after the bodies of multiple women with the same physical description are found scattered across the city. Meanwhile, Maggie juggles her roles as a guardian to Ella and an FBI agent.
After a park ranger is shot dead by a masked assailant on Governors Island, the team discovers a string of connected crimes that leads them to their toughest roadblock yet: an online conspiracy theory community.
The investigation into an assistant U.S. attorney’s death leads the team to a related airline whistleblower scandal and the chilling discovery that they don’t have much time to thwart terrorists from crashing numerous in-flight commercial airplanes. Dealing with the memory of his brother, who was a 9/11 victim, the case pushes Scola hard to prevent another catastrophe.
Jubal's longtime confidential informant brings intel of an impending large-scale terror attack to the team, but when the details don't add up, Jubal must sift out the truth from a man who's known him at his worst.
When the team’s sex trafficking sting operation goes sideways, they race to recover a human trafficking victim. Meanwhile, Maggie makes a connection with a 911 operator to help find the girl before she is whisked out of the city or worse.
After two jurors for a high-profile mafia trial are gunned down, the team jumps into an organized crime investigation until it is discovered that the jurors may not have been the intended targets at all. The case becomes personal for Scola when he learns that one of his former drill instructors from the military academy he attended may be linked.
When a passenger train is hijacked and rerouted while at high speed with an unarmed OA and Gemma on board, the team races to wrest control away from the unhinged perpetrators and prevent a catastrophe.