Morning rush hour on the London underground and Laurie Bateman is on her way to work when she witnesses a terrible accident. The elderly gentleman next to her on the platform falls onto the tracks and is fatally injured. With the police uninterested, Laurie is drawn to investigate and soon finds herself breaking into the tube network in the dead of night searching for a clue dropped by the dead man, only to be pursued by two unknown assailants whom she narrowly escapes.  But Laurie's troubles are far from over and soon she loses her job, has her phone stolen and discovers her flat has been burgled and her flatmate assaulted. It takes her father to persuade her that everything might be connected. Laurie starts to dig deeper, unaware that as she gets closer to the truth, she is endangering not only herself, but also everyone she loves