Ex-military policeman Jack Reacher arrives by train to a small town called “Mother’s Rest.” There he meets Michelle Chang, an ex-FBI agent who is looking for her colleague, Kiv(er). The locals behave hostilely and suspiciously, and Reacher decides to help Chang…
A former FBI agent explains that Kiver called her in relation to a case involving a client unknown to her. During a search of the room where Kiver had been staying, Reacher finds a crumpled note with the name “Malloy(n)e” and a phone number for the science editor of the “Los Angeles Times” named Westwood. After contacting the journalist, Jack learns that he takes calls connected to a conspiracy theory. Reacher and Chang begin searching for Malloy(n)e. In Mother’s Rest, locals attack them, but Reacher manages to come out victorious.
Reacher and Chang visit Kiver’s home and find evidence of a search. Jack is convinced that Kiver stumbled upon something and was killed for it, and they head to Los Angeles to meet Westwood. The journalist gives Reacher phone numbers of several people—one of whom could have been Kiver’s client. Jack and Michelle discover that Malloy(n)e is actually a Chicago resident named Peter McKen(n).
When they go to McKen(n)’s home, they find that he’s missing. A killer named Hackett attacks them, and Reacher knocks him out. Then they learn that Peter has a sister. At her house in Phoenix, they are attacked again by hired killers acting on orders from the leader of a Ukrainian organized crime group named Merch(en)ko. Reacher finds the Ukrainian man and kills him.
Back in Los Angeles, Reacher and Chang meet with Westwood. Jack claims that McKen(n) was looking for his son Michael, who suffered from an inability to feel joy and spent most of his time online. With the help of a hacker recommended by Westwood, Reacher finds out that Mother’s Rest provides euthanasia services.
At Mother’s Rest, Jack and Michelle find an illegal film studio where real murders of people with suicidal tendencies were being filmed. After dealing with the criminals, Reacher and Chang set off together for Milwaukee.