Fresh from a high-profile case in the Paris fashion world, elite forensic psychologist and criminal profiler Dr Alexander Gregory receives a call from the FBI.

The wife of a notorious criminal has been admitted to a private psychiatric hospital and can no longer testify in his upcoming trial.

Without her, their case will collapse but, amidst reports that the staff are as unpredictable as their patients, who can the police trust?

In desperation, they turn to an outsider and now Gregory must find the courage to step inside the fortified walls of Buchanan Hospital to uncover the truth.