The gripping third novel about ex-detective Reuben Maitland takes us on a breathtaking hunt for a killer who is targeting people on the London Underground.Reuben Maitland is a forensic scientist forced to work outside the law. Fired from the Criminal Investigations Department, he takes work where he finds it. But when he discovers that his long-abandoned study on Behavioural Profiling, to predict latent homicidal behaviour from people’s DNA, is being put back on track at his old unit, GeneCrime, he knows he has to act.Rogue elements within GeneCrime believe that prevention is better than cure, and are using Reuben’s research to hunt down and incite innocent people beyond their breaking point.Reuben turns to the one person in GeneCrime he can trust, DCI Sarah Hirst. But the GeneCrime unit is frantically trying to stop a seemingly invisible killer who strikes in the middle of the day on busy Underground lines. As the body count escalates, panic sets in and London life threatens to grind to a halt.Drawn back into GeneCrime by his feelings for Sarah, Reuben starts the hunt for the people misusing his technology. Only Reuben knows that the Behavioural Profiling technology is dangerously flawed, and innocent lives are threatened. But what he cannot know is that this hunt will lead him directly into the path of the Underground Killer.