When a chauffeur driving a high ranking British government official reaches his destination, he is horrified to discover that his passenger has turned into a skeleton...! Clearly a case for Department S.The detectives start investigating, wondering whether this was indeed the man's skeleton, or if some sort of switch has been made. Stewart is supposed to meet Sir Curtis on a train for an urgent briefing, enters the compartment and finds - another skeleton...In the hopes that the bones are fake and their boss is really still alive, the agents are racing against time to unravel the mystery of the skeletons. Stewart and Annabelle have to pressure high ranking military officers into revealing classified information, while Jason follows a lead to a hotel. When Annabelle is about to meet him there later, she only finds another skeleton... as does Stewart on a plane from New York, where an American official has seemingly turned into a bonesman in midair. It takes a journey in a cargo container to find out what - and who - is behind it all.