Captain Flint is warned about Billy, Vane encounters someone from his past and Eleanor asks her father for help. Meanwhile, the crew of The Walrus suffer a disastrous undertaking.
John and Max put themselves in danger, with both Flint and Vane determined to get hold of the map. Meanwhile, Eleanor finds that she must make a difficult decision.
Police searches Billy Hobson's murder scene again. Frank and Joe come up with a plausible theory how to tie together all three murders. Dani tries to kiss Frank but is rejected. Poppa T with his crew turn on Damon and empties his safe, on their way out shoot-out occurs and Michael is shot.moreless
Luther tasks Ripley with leading the investigation into Cass's murder, while he re-examines cold-case files in an attempt to predict the serial killer's next move. Det Supt Stark increases the pressure on Ripley to turn on Luther.moreless
Luther has to juggle two investigations as he tries to stop a copycat serial killer who is murdering women in the manner of an unsolved case from the 1980s, and establish which of many suspects might have murdered a man who used the internet to torment his victims. Unknown to Luther, his every move is being watched by officers from the anti-corruption unit, who are determined to expose him.moreless