Emily Hammond is killed in her flat by a fetishist who makes up and wigs her corpse,the slaying recalling the murders thirty years earlier by a serial killer the Shoreditch Creeper,who had connections with Emily's house. At the same time Ripley is introduced by embittered Erin Gray to creepy,'unretired' superintendent Stark, anxious to nail Luther for killing people who eluded justice and taking the law into his own hands. Stark and Gray put a wire on Ripley as he and Luther investigate the apparently ritual murder of obscene Internet troll Jared Cass. Prime suspect is Ken Barnaby, who was plagued by Cass with taunts over his dead daughter but Luther feels sorry for him,warning him of likely arrest which spurs Ken to take extreme action. Luther finds romance with Mary Day after they literally bump into each other in a traffic prang but the killer strikes again,murdering Dani Lane, who was Emily's baby-sitter in the 1980s, and her husband. Written by don @ minifie-1

Luther investigates the Lanes' murders, noting that Dani has been made up in the same way as Emily. He also discovers that Ronnie Holland, who headed the Shoreditch Creeper case, has died in suspicious circumstances. Aware of Ripley's involvement with Erin Gray he confronts her and tells her not to use the sergeant in any vendetta against him. Luther discovers that Holland was obsessed with a former murderer William Carney, now debilitated and in a care home. Furthermore Carney has been receiving regular visits from a mysterious man called Paul Ellis. From speaking to Carney Luther works out that the serial killer, a disciple of the Shoreditch Creeper, is enacting revenge on women, having murdered his mother for being a whore, and thus cracks the case. Ripley arrests Ken for killing Cass but Luther manages to get him back on side. Written by don @ minifie-1

Still fishing for dirt on Luther, the desperate Gray and Stark visit Mary, suggesting that Luther killed his wife. However Gray begins to sense that Stark is getting out of control in his desire for revenge and confides in Ripley. Meanwhile a young couple are saved from an attack by thugs by a mysterious man who shoots two of the assailants dead. Both of the dead pair are convicted killers and later another man who had been charged with murder is found hanged. Through a website, Luther discovers the perpetrator to be Tom Marwood, taking revenge on killers freed by the system - such as the murderer of his wife Caitlin. He next abducts a paedophile Dennis Cochran, whom - following a public vote of approval on the Internet - he hangs. Luther and Ripley track him down but he steals Luther's phone and shoots Ripley before making his escape. Written by don @ minifie-1

Luther discovers Ripley's corpse and is charged with his murder by Stark and Gray, but whilst in transit the police car is attacked and Luther is rescued by Alice Morgan. After Marwood goes on the rampage at Luther's flat Superintendent Schenk is aware that he killed Ripley and Mary is taken to a hideaway by Stark and Gray, though Gray starts to sense that Stark wants to reel Luther in for a confrontation. Marwood meanwhile abducts the wife of the doctor at the prison where Caitlin's murderer is held and threatens to kill her unless the doctor gives him a lethal injection. Alice and Luther track Marwood down but he escapes, locating Mary via Luther's phone. He kills Stark and wounds Gray but Alice and Luther arrive for a roof-top showdown. Written by don @ minifie-1