Ben brings coffee back to the motel room after he spends the night with Mary. She regrets calling him and leaves him, saying she has to get to work.
At the station, Frank plans on interrogating Des. Ben confesses to Frank that he spent the night with Mary.
Mary spots Grady wandering around behind her house and confronts him. Grady has figured out what she and Des are doing with the pento they buy off him and demands a cut of the profits.
Ben tails Mary while Des is meeting with a new client, Morgan. Arriving at Mary's destination, he calls in a check on the addrss but jumps out of his truck when he hears gun shots. He runs around the house and finds Mary and her sister, Nicole, shooting at beer cans on the dock. Mary introduces them and Ben gives her some pointers on shooting.
Des is sitting down with Morgan, the Cystic Fibrosis patient Annie referred earlier. They have a good talk and Des commits to helping him once he consults with Mary. He mentions that he and Mary had a fight and Morgan suggests that life's too short to fight with friends, advising Des to apologize and make peace.
At the hospital, Annie is told to report to the board room by an administrator. The administrator asks her about Sid's disappearance from the hospital the day before. She questions why Mary would transfer Sid from ER to ICU when his injuries weren't life-threatening.
Des calls Mary while driving away from Morgan's house and leaves a long voicemail. Frank pulls him over and insists he comes to the station with him. Des refuses and Frank arrests him. In interrogation, Frank questions him about Troy Dixon and insinuates that Mary has been telling Ben about the business. Des doesn't buy it and lawyers up.
Mary tells Nicole about what she's been doing and why Ben is following her. Mary and Ben take a walk and share their childhood stories. Ben tries to question her about her clients. Ben reveals a lot of details about his case including how Judge Grant put him undercover to find out what happened to his son. The station calls him to let him know that the address he asked about belongs to Nicole Mitchell. When he realizes the sisters don't share a last name, he asks the officer to run a check on a Mary Mitchell.
Back in interrogation, Des is sharing his feelings about his clients with Frank just as his lawyer walks in. Turns out his lawyer is Louise, Naomi's mother. She gets him released without charges. Frank offers her the chance to have Des' involvement in a murder waived if he wears a wire to gather info on his partner.
Jess and Naomi hit the beach but Naomi's actually more interested in meeting up with Tristan than spending time with Jess. Naomi pulls out a bottle of pento and Jess freaks out, grabbing the bottle and stomping on it. She accuses Naomi of having a death wish and storms away from the others.
Over Chinese food, Des and Louise discuss the immunity offer.
While Ben takes a call from Frank, Nicole and Mary discuss him. Nicole advises her to come clean with him and see if he can help her. Frank tells Ben that Mary was investigated for her mother's murder, that she didn't die of cancer but was found dead in the lake with her hands tied behind her back. Mary comes out to talk to him and he demands an explanation for her mother's death while recording their conversation with his phone. She asks him to leave.
Mary checks her voicemail and gets Des' message. She tries to call him back but he's meeting with Grady at that moment, trying to purchase heroin. Grady doesn't believe him and tells him about meeting with Mary earlier that day. Des thinks that Mary's sold him out, tells Grady he's done with Mary and just wants a fix. Leaving Grady's place, he calls Louise and says he'll take the immunity deal.
Nicole and Mary discuss their mother's death. They helped her die when Mary was sixteen and Nicole says that they saved her then and Mary is still saving people now. Mary tells her that she charges her clients for the service and that she likes helping people die and doesn't think she can stop doing it. She worries that she's "crazy like mom" and Nicole assures her she isn't anything like their mother. Suddenly, she shoves her into the water just to see if she still has the will to live. Nicole jumps in with her and they share a laugh.