In 1982, two teenagers, Emma Lewis and Travis Bell, are recruited to the FBI's Behavioral Science Unit to interview convicted juvenile killers and provide insight and advice on cold cases. Both have experience with serial murder: Emma is the only survivor of murderer Daniel Huxton, and Travis's U.S. Marshal father died while trying to capture a teenage serial killer.

From the start, Emma and Travis develop a quick friendship, gaining insights and knowledge from convicted juvenile killers that even the FBI couldn't crack. But when the team is called in to give advice on an active case -- a serial killer who exclusively hunts teenagers -- things start to unravel. Working against the clock, they must turn to one of the most notorious murderers behind bars for help: teenage serial killer Simon Gutmunsson.

Despite Travis's objections, Emma becomes the conduit between Simon and the FBI team. But while Simon seems to be giving them information they need to save lives, he's an expert manipulator playing a very long game....