Lacey Flint is a tough cookie. When selected by the special crimes division of the Metropolitan Police (SO10) to an assignment under Detective Inspector Mark Joesbury as an undercover agent, Lacy takes on the persona of Laura Farrow. The London officer, posing as a student at Cambridge University, is given the former room of the college’s most recent suicide attempt—an apparent self-immolation. Given a growing number of suicides on the campus, Scotland Yard and the Metro police have launched a covert investigation; Lacey/Laura serves as their eyes and ears.

With orders only to report by email to DI Joesbury—a man for whom she secretly harbors an unrequited passion—Lacey’s first taste of college life is a kidnapping/hazing incident from her dorm room. Buckets of icy water are thrown at her while padlocked to a tree in front of a crowd of cheering students, their cell phones capturing her humiliation, an apt beginning in a tale with malicious overtones and suggestions of pressure from outside sources on suicidal students. Working closely with Dr. Evi Oliver, a psychiatrist/ professor who has counseled some of the troubled students, Lacey learns more of the bizarre details around the deaths.

But Bolton does one better in a mystery that combines external forces with the vulnerability of the mind when suicide is at stake: the book opens with Lacey in a precarious position, her immediate decision a matter of life or death. Everything in the novel moves toward that point where Lacey will either survive or perish. In the preceding pages, while meeting frequently with Dr. Oliver and emailing Joesbury faithfully, Lacey/Laura learns the particulars of the deaths, from self-immolation to self-decapitation to hanging from a noose tied to a tree. Each of the students had a history of psychological problems, most of them were beautiful young women.

While Evi Oliver is bedeviled by a stalker who leaves no clues for the police, increasingly haunted by a traumatic incident in the past in which she lost a patient and the man she loves, Lacey is beset with hallucinogenic nightmares she can’t remember the next day, much like the other girls prior to their suicides: “It feels like someone’s been in my head… finding all the things that I’m most scared of and using that knowledge.” Regardless of her training and survival instincts honed in a troubled childhood, Lacey can’t seem to control the haunting dreams or her impulse to share her distress on Internet discussion boards: “It hadn’t been only Laura in the chat room just now. That had been Lacey too.”

Known for her superb plotting of nail-biting thrillers, Bolton masterfully orchestrates the destructive ingenuity of a group of sociopaths with the vulnerability of young girls under too much pressure at a prestigious university. Thinking herself immune, Lacey learns a terrifying lesson that leaves her—and us—on the brink. A darkened Cambridge spreads out below, stars twinkling above and a desperate Joesbury—carrying his own torch for Lacey—too far away to help. Filled with menace and the insidious doubts of a mind under constant assault, this is Bolton’s most devastating novel to date.