Which victim will be the last? When a man arrives at Swindon police station declaring it's his 'death day' before taking his own life, DI Silas Hart is shaken. Days later, another man dies in the same way, the small hourglass lying beside him the only evidence police have to work with. The trail leads Hart to disgraced psychiatrist Dr Garstan, whose controversial research claims to predict the moment of death. Both victims were his patients - but what really happened to them? To uncover the truth, Hart's partner goes undercover. But probing the mind of a psychopath is dangerous work - and the price of discovery could be far more than her life.