Luther returns to work after a traumatic arrest to investigate the murder of a former child genius's parents, and quickly deduces that their daughter is responsible. However he is unable to find evidence to convict.

A gunman is murdering uniformed police officers, and warns that there will be further shootings unless his terms are met. Luther is determined to flush the killer out.

John Luther is on the trail of a satanic occult killer who kidnaps a woman but leaves her baby in the living room. Things get harder when a man accuses Luther of attacking him. Things take a grisly turn when the woman is found.

When a serial killer goes on the rampage, Luther must put his personal life aside and delve inside the murderer's mind to discover what is driving him to kill so many girls, and why.

Luther and the team are after the people involved in the violent kidnapping of Jessica Carrodus and they are in search of diamonds.