After an operative kills all but one of the employees at a marine biology research group, McCall and the team join forces with Colton Fisk when they discover a connection between the murders and a secret CIA program he was involved in.

The team is put into harm's way when McCall's former CIA colleague is found alive and sets her sights on revenge by attempting to abduct Dante, Harry and Mel. Also, Aunt Vi and Delilah must act quickly to de-escalate a hostage situation of their own when a robber targets a bodega. Third season finale.

McCall races to save the team after they're put into extreme danger by her former CIA colleague Michelle Chambers while she discovers the truth behind the CIA withdrawal in Venezuela that led to the death of one of her friends.

After Mel is reunited with her brother, McCall helps him blow the whistle on his former unit's unethical practices before it's too late. Aunt Vi and Trish's relationship becomes fractured by Vi's need to protect McCall's true identity.