As a covert officer specialising in 'deep cover' operations, Marie Donovan works amongst dangerous criminals. It's a precarious life that puts Marie on the edge of the law. When she begins an affair with Jake Morton, an informer due to give evidence against crime lord Jeff Kerridge, Marie knows she's breaking a cardinal rule.

A massacre in the Scottish Highlands is far more than the family tragedy it first appears to be, in this riveting police procedural. The slaughter of the Dawson family seems to be a heartbreaking case of murder-suicide—another deeply troubled man who violently snapped and killed his wife and children before ending his own life. But DI Alec McKay doesn’t think it’s as open-and-shut as it looks. Why was a BMW parked at the Dawsons’ holiday home on that last day of tourist season—and why are its owners also now dead? Why is the new senior investigating officer acting so erratically?...