Reilly and Maddox's working relationship comes under pressure when, in the course of the investigation, elements of their pasts emerge that they would rather forget.
Despite Rob's promise to Cassie that they won't investigate Operation Vestal, they make a dark bargain to keep the secret and carry on working on the cases.
As Cassie struggles to make sense of Lexie's life and death, we delve into her own difficult past. Meanwhile, Rob's past finally yields some results in the Katy investigation.
When Cassie immerses herself in a undercover assignment, threats both known and unexpected haunt her every living breath. Rob desperately hunts down one last lead.