When former Detective Inspector Jessica Hirsch boards the London Underground, it should be just a few short stops home at the end of another long day. But as the tube barrels from Baker Street, it's brought to an abrupt stop – there is an electrical fault, leaving the train stranded. And then she hears the scream. As the lights go out, Jessica pushes through into the driver's cabin. There, she finds his lifeless body, a knife embedded deep in his back. But if nobody could get into the cabin from the outside, and nobody could get into the front carriage, the realization strikes hard-there's a murderer among them, concealed within the confines of the carriage. With no escape from the train, and in the pitch black, Jessica is thrust into a deadly game. Every passenger becomes a potential threat, and time is ticking relentlessly. In a race against the unknown assailant, Jessica must unravel the sinister truth before the killer strikes again…
