In 1982, in the USA, the innovative FBI Behavioral Science section is breaking new ground, and two teenagers - Emma Lewis and Travis Bell - are recruited to interview convicted juvenile killers for information on cold cases. Emma and Travis are untrained but they've both experienced violent crime, which has given them skills that make them valuable to the FBI. When they are drawn into an active case targeting teenagers, everything starts to unravel. Over Travis's objections, Emma becomes the conduit between the FBI and Simon Gutmunsson - a super-intelligent, nineteen-year-old sociopath. And although Simon seems to be giving them the information they need to save lives, he's also an expert manipulator playing a very long game... Working against the clock, can Emma and Travis stop a serial killer in their tracks - or will they fall victim themselves?