A new spate of nightmarish murders brings DCI John Luther to once again face the depths of human depravity on the streets of London; as the body count rises, Luther attempts to catch a killer and save his own neck.
Luther must confront a demon from his past, as both the police and Cornelius converge on his home; with Halliday convinced that the body in the morgue isn't their killer, Luther attempts to put his own troubles aside and find the true murderer.
With his friend in peril and a young woman kidnapped by the relentless serial killer, Luther tries to protect the innocent while preventing Cornelius' violent revenge from consuming him.
Luther takes a leave of absence from the police; when an old colleague brings him a shocking piece of news, he is drawn into investigating the crimes of a gruesome killer.
News of a murder interrupts Luther's date with Mary; Ripley must investigate the Jared Cass murder alone.
A vigilante killer is determined to punish past offenders; the campaign pushes Luther to his limits.
Luther must clear his name after being accused of crimes he didn't commit while working to stop the vigilante killer.
Luther returns to work; a failed art student wants to emulate a Victorian killer; Luther agrees to help a widow.
Luther sets out to rescue Ripley after he is abducted by Cameron; Jenny's boss demands compensation.
Luther's life spirals out of control; a killer's actions are ruled by dice.
Det. John Luther returns to work after the traumatic arrest of a serial killer; Luther investigates the murder of the parents of a former child genius.
Luther must outsmart a sniper on a mission to gun down police officers; Luther discovers Alice has been investigating him.
Henry Madsen wakes up from his coma, putting Luther's career in jeopardy; three girls are found murdered, forcing Luther to put his personal concerns aside.
Luther begins a tense investigation when an art dealer's wife is taken hostage.
When Luther is framed for murder the only person he can turn to for help is Alice Morgan.