A school trip to the National History Museum of Wales at St Fagans ends early with the disappearance of a child.Is he just playing hide and seek or is it the work of a criminal? Perhaps a kidnapper with designs on the boy's mother and her recently-acquired millions?DCI Martin Phelps and his team are back together just in time to take on the caseone that starts off as a possible kidnapping but soon descends into something even more sinisterAs the investigation exposes the complexities of family relationships, another long-standing mystery is solvedall while Martin and his colleagues anxiously await the results of a major police review that may result in them losing their jobs