John Luther is Detective Chief Inspector of the Serious Crime Unit. His intelligence and physical prowess make him an asset in the field, but will it cost him too much personally? Can he keep his relationship with brilliant psychopath Alice Morgan purely professional?

Alice Morgan was a child prodigy who gives off the attitude of an innocent victim as the people around her are murdered. However, Luther becomes convinced that she is the killer. Is Alice innocent or a brilliant murder mastermind?

Justin Ripley is new to the detective force and idolizes John Luther. He is young, eager, and ready to learn on the job. Justin and Luther eventually form a bond and Justin becomes his protégé.

Martin recruits Luther to be part of the Serious Crime Unit. As Luther’s boss, he reigns in Luther while still giving him the liberty to solve crimes in his specific way.

Benny is an extraordinary hacker. He’s more comfortable with computers and technology than social interactions. Like Luther, he’s willing to go above and beyond the job in order to solve to a case.