On a summer's day, at a remote lake, three members of the Fowler family take a dinghy out onto the water, leaving mother Sarah at the shore. Less than a minute later, she checks to see where they are. The boat is empty. Sarah's family have gone. At the Skyline Casino in London, the security team have just made an arrest: they've spotted and detained a man suspected of murdering a high roller. After locking him in one of their holding cells, the team station themselves outside and wait for the police. But when the cops arrive, they find something impossible. He has vanished. David Raker is an expert at solving missing persons puzzles - these mysteries are unlike anything he's ever seen. As he digs into the Fowler's, his long-time ally - ex-detective, Colm Healy - tries to get to the bottom of what happened at the casino. The men are in danger - a deadly secret that was never meant to come out is about to.