Mary observes to Des that this is why she started doing what she does. Des brings up Joel and Mary mentions that she’s been researching the type of cancer he has and the new treatments that have been developed. Des thinks she’s trying to save Joel now because they had sex.
Mary meets Joel in a diner with bad coffee. It’s an awkward meeting. She shares that she used to waitress when she was in med school since she had no parents to help with tuition. Getting down to business, she offers him a spot on a clinical trial treatment program. He walks out and she follows, trying to convince him to give the program a chance. He’s wearing a wire and tells his partner that he’s going to roll with it. He tells Mary that fixing him isn’t what he’s looking for and drives off before she can tell him anything else.
In a hospital room, Charlie is visiting his dying mother, Yvonne. Nurse Annie comes in and they tell her that Yvonne wants to go home. She doesn’t want to undergo any more treatments or spend any more time in hospitals. When Annie offers to connect them with palliative care, Yvonne gets Charlie to ask how much morphine it would take to die. Annie can’t answer but offers to connect them with “end of life” counsellors.
Annie passes Yvonne’s file to Mary. She advocates to put a rush on it since she promised Charlie she’d help ease his mother’s pain quickly.
Joel’s partner, Frank, phones Mary, pretending to be one of Joel’s doctors. He discourages Mary from pushing Joel towards clinical trials, saying that Joel has suffered enough. She takes the bait and agrees. Hanging up, Frank and Joel discuss the judge who put them on this case. Joel examines the murder board they have for Mary, connecting her to their “Patient Zero”, a young man named Ethan Grant, the judge’s son.
At home, Mary keeps the pento inventory in her bedroom now. Her daughters come in before going to their father’s. Jess shares that there’s a party this weekend and that Naomi is milking her fainting incident for attention at school. Cambie asks where Casper the cat has gone and Mary has to tell her that he had to be put down because he had cancer. Dropping them off at Kevin’s, they exchange pleasantries with Louise and Naomi, who is still wearing her hospital bracelet. Cambie shares the news about Casper and asks for ice cream to make herself feel better. When they’re alone, Kevin pressures Mary for the rest of the child support she owes him.
Just as she’s headed to meet Des at Yvonne’s house, Joel phones Mary, sounding distressed and says goodbye, indicating that he’s just going to shoot himself. Mary drives straight to his place and promises to help him. With cameras recording everything in his apartment, he lies down and hands her the envelope of cash. She doesn’t want it but he insists. She asks if there is anyone he wants to say goodbye to. Joel takes a moment and asks her to describe how she’s going to kill him. Mary gets suspicious and asks to use the bathroom where she realizes that he has no medications in the bathroom. Coming back into the apartment, she tells him she needs a file from her car and then runs, calling Des to let him know that Joel is a cop. With her car penned in by a pizza delivery guy, she dumps the pento through a storm drain just as Joel, tipped off by Frank, runs out and tries to force her to take the money. She tells him that his behaviour is too erratic and scares her and, once the pizza delivery vehicle moves, she drives away as fast as possible.
Jess and Naomi are at the party and are offered cocaine. Jess declines but Naomi does a line. Jess leaves.
At Yvonne’s house, Des has to tell Charlie that they can’t help his mother die that night. Before he gets the chance, Charlie shows him a video Yvonne made, explaining that she’d lived exactly the life she wanted, her hopes for her son, and that she was leaving this world by her own decision. Touched deeply, Des still has to tell Charlie that they need to postpone the suicide. Charlie pulls a gun and gets him to call Mary. Mary tells Des that she dumped the pento. When Des explains and tries to leave, Charlie shoots him in the shoulder.
Mary offers to go to Des’ dealer for more pento. Des warns her that Grady is a bad guy. When she arrives, Grady insists she take her shirt off to check for a wire. He reveals that he knows exactly who she is and where she lives. He gives her the pento, takes a picture of her, and she rushes out.
At the police station, Joel and Frank are meeting with Judge Grant to explain they don’t have enough incriminating evidence to charge Mary yet. They know about Annie’s involvement but warn that if they burn her as the liaison, they lose Mary. The judge is impatient but wants Mary arrested for murder since his son was too young to give consent for assisted suicide.
Back at Yvonne’s, Des is triaging his bullet wound while waiting for Mary. He notes that Yvonne is close to the end and mentions that he used to be a doctor too but lost his license. Mary arrives, disarms Charlie gently, and starts to prep the drugs. She reminds Des that Yvonne can’t swallow due to the ALS she suffers from so they’ll have to inject her.
Charlie turns on Yvonne’s favourite song and tells his mother he loves her. Mary injects the pento and Yvonne opens her eyes to look at Charlie one last time before slipping away peacefully. Charlie breaks down in tears.
Mary takes Des back to his place to get him cleaned up. He assumes that with Joel being a cop, they won’t be doing anymore jobs but she insists that they need to keep helping people, just be smarter about it. Des takes it a step further and starts pitching branding ideas for when euthanasia is legalized. Mary asks about Casper and Des admits that he probably left the windows open and hasn’t seen Casper for a while.
Jess and Naomi discuss what happened at the party and Naomi admits that her passing out at the ballet recital was due to drinking the pento they’d found in the shed. She also reveals to Jess that Mary knew about the pento.
Mary gets a call from Troy Dixon’s widow as she drives home but hangs up.
When she gets home, Joel is waiting for her. She confronts him about lying and he reintroduces himself as Ben. She points out that he has nothing on her and heads into her house.