Nick takes some time off work to spend time with his family but Alice say she can’t because she has to work, where she has another tryst with Jack. 

Alice left her laptop at home on which Nick finds a direct message chat she’s been having with someone who says they have to talk about “him.”

Nick has Flynn skip school so the two can spend the day hiking. Later, he and Alice fight. She tells him he has been shutting her out since the miscarriage and he accuses her of having an affair. When she denies it, he storms out, heads to a bar and gets drunk.

Nick turns up at Emily’s. He tells her that Alice is cheating on him and then wants to have sex but Emily turns him down. She says they can’t go back and he leaves. 

The next morning Nick and Alice talk. He tells her about the lie he’s had to tell for work and how he thought he was going to be killed in the woods. He also admits that he pulled back from her and Flynn when they needed them most. Alice tells him she can’t have children, but she doesn’t mention her affair with Jack. 

The department is calling Tommy’s death carbon monoxide poisoning. His Captain tells Emily that she had to suspend Tommy because he broke into Catalyst Diagnostic. Emily has Jack look at the autopsy report but it reads like a suicide.

Jack tells Emily he’s seeing someone and he’s happy, but he doesn’t want to say who it is just yet. 

Crown wants to close the case of the Fentanyl Killer now that Wolfe is dead but Cal and Emily push to find out who ordered the killings and why.  Crown is worried because the Deputy Director has a close relationship with Julianne.

Emily tells Cal about the Catalyst Diagnostic connection and Tommy’s death. Cal and Emily learn that almost all of their victims had a medical connection to Catalyst. They also learn that Wolfe pretended to be a visiting nurse to give Nathan Farley a flu vaccine.

Emily tells Cal she’s still looking into the foster kids from Barrett House. 

Cal and Emily learn that Catalyst might have links dating back to something called the Quill project that began in the 1970s but was shut down. They track down Dr. Ulf Maston who was in charge. The project was meant to help control PTSD but the results weren’t what he expected. He’s been testing on rats. The serum makes them handle stress better but it also makes them much more violent and aggressive, sometimes even murderous. 

Dr. Maston says his former colleague was a behavior psychologist , Dr.Lu-Fang-Shen, the same man who tortured the kids at Barrett House. She’s even more shocked when she sees an old photo on the wall that include’s Flynn’s therapist. Dr. Semo Oduwale.