When a local club owner is found dead, the team works quickly to find the motive behind the murder of a seemingly innocent man. Meanwhile, OA is smitten with a new love interest but is concerned that she's mixed up with the wrong crowd.

After multiple people are targeted and killed with a poisonous gas in broad daylight, the team races to find the killer, who they believe is tied to an eco-terrorist plot. Meanwhile, Maggie continues to explore motherhood.

When a retired FBI agent is tortured and killed while working a security job, Scola and Nina go undercover as a married couple deep in the diamond game as the team tries to find out who is responsible. During the course of his and Nina's dangerous assignment, Scola is plagued by the possibility that their son Doug could end up parentless.

When a truck driver is murdered and the drug he was transporting goes missing, the team hunts for those behind the remaining batch that is already wreaking havoc on the streets of New York.

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.