DCI Luther investigates the violent kidnapping of Jessica Carrodus by a gang intent on recovering a batch of stolen diamonds. They've given the woman's husband James an hour to deliver the goods and as proof of their seriousness, have already cut out her tongue. Luther, always ready to bend the rules, retrieves diamonds from another case in the evidence locker but the delivery goes wrong. It's also revealed that one of Luther's colleagues was in on the original robbery. In the midst of all this, Luther's wife Zoe has decided to break all contact with him. When he finds her dead on her kitchen floor, he realizes all of the evidence will point to him as the killer and he goes on the run.
—garykmcd