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.