Detective Ben Westphall has been given his latest case because of his background in MI6. But in this series debut, nothing can prepare him for the case of John Baden, a man who died 12 years ago—but just walked in to a police station, very much alive. Westphall travels from the Highlands to Estonia in order to delve into Baden's murky past, but when his suspects start dying, he realizes someone is killing to cover up the truth.