It was Peter's idea to invite his friends on a joyride on Justus' birthday of all days. In pouring rain, a car breakdown forces the three detectives to seek refuge at the creepy "Blackstone" castle. When lightning knocks out the power line, the three investigators are stuck for good. It soon becomes clear to the three junior detectives that the lord of the castle, Count Gallagher, is a real chess fanatic. But not only that - the old castle makes a spooky impression and then there is Moe, the count's sinister servant. What is it about the chess pieces on the dilapidated, centuries-old chess table that seem to move by themselves, move after move, as if by magic? Is the old building really haunted? The first detective is immediately hooked and senses a new case, only Peter wants to run away. It soon becomes clear to the three investigators that this is about much more than just a game of chess...