His next stop might be your last . . . As a killer stalks the London Underground, an online group’s true crime investigation takes a dark turn when they are infiltrated by the murderer…

In the early hours, amongst the chaos of London’s morning commuters, a severed head is discovered on the Tube line, with a message – ‘I’m back.’ 

Former investigative journalist Janica is one of the first on the scene. Recognising the MO from a previous case and convinced that a serial killer is poised to strike again, she teams up with an online group dedicated to cracking unsolved crimes. Together they are determined to gather the evidence required to hunt the perpetrator down.

But it isn’t long before their target realises they’re onto him. As the murders escalate and terror spreads throughout the Underground, Janica finds herself caught up in an obsessive game of cat-and-mouse that’s about to take a terrifying step from the online world into real life. She will need all her wits to get into the mind of a monster . . . unless he finds her first.