In the latest episode of BBC One's "Luther," it seems Luther will find out something shocking about all the recent crimes and will be compelled to put Emma in danger to stop it.

What discovery does Luther make and why does he have to put Emma's life in danger? To watch, CLICK HERE.

According to the synopsis of the episode, on the trail of a cannibalistic killer, Luther is dogged at every step by ghosts from his past. Isolated and on edge, it takes him every fibre of his being to keep it together.

Could a cold case help unlock a mystery that's tormenting him?

Meanwhile, the serial killer is still on the loose. Benny's hacking skills have revealed a list of hundreds of potential victims, but, with a rapidly escalating number of crime scenes, Luther must use all his ingenuity to work out where the murderer is headed next.

Discovering it's all part of a macabre endgame, Luther is forced to put himself and his new colleague Emma in the heart of danger to try to stop the killings.

In the Season 4 premiere episode, on a leave of absence from the police force, Luther was lying low in a rundown cottage on the edge of England but a visit from his old colleagues at the Met brought a shocking piece of news that drew him back to London in search of the truth.

Meanwhile, a gruesome serial killer had struck the city. With a trail of clues leading from one crime scene to the next, Schenk and his team worked out the twisted logic that connected each victim, but this murdering mastermind was more than a match for the police, outsmarting them at every step. It's not long before Luther was back in the Bullpen, determined to steal a march on the killer before it's too late.