Ben follows Mary to her childhood home where he learns about her past. Grady approaches Mary with an offer. Des becomes a victim of police misconduct.

Mary must make a deal with the devil in order to save her family and career.

When Olivia attempts to blackmail Mary, she is drawn deeper into a deadly game of cat and mouse that has a surprising connection to Ben.

Following the disappearance of Travis, Des worries that he and Mary may have crossed a moral line from which they can never return. After jeopardizing Ben's investigation of Olivia, Mary tries to make amends, which has repercussions for a patient in dire need.

All seems well for Mary, Ben has forgiven her, and she and Des have decided to move forward with the death retreat. The only nagging concern for Mary: her daughter Jess hates her and doesn't believe a word out of her mouth.

Mary decides to wear a wire in order to help Ben take down Olivia, but when their plan takes an unexpected turn, Mary must reconsider her allegiance. As Des and Nicole prepare for Brendan's death, Des faces crippling self-doubt about his dream.