Tom, Mirjam and Snuf are heading out to do research and discovers the way ''Vliegende Volckert'' manages to escape every time.

Tom, Mirjam and Snuf are staying over on a farm, where they bump into a dangerous smuggling ring. They move to an old haunted castle, while Snuf notices something strange.

Tom is sure that he saw someone at the haunted castle, but nobody believes him. Nephew Jaap has his attention only for Mirjam and jealousy is seperating them. After a fight with Jaap, Tom goes out for research together with Snuf. Snuf follows a trail that leads him to a secret passage.