Summary Tom's gang strolled around in the old ruin and stumbled upon a secret society, dressed as Huguenots. Tom tells his father, police commissars Sjoerd van Hulle, but he can't even find the ruin, so he tells his colleagues the kids' imagination must be running wild after their recent kidnapping adventures. Meanwhile father attends a municipal meeting to prepare the reenactment of the royal chess game for the city, as the present Dutch king Willem Aleander will attend and play his ancestor Willem II, while the mayor plays the stadholder. EXtensive safety measures are planned, requiring help from neighboring police departments. During a museum visit in preparation for the school's musical version of the event, the kids notice the Hughnetos they saw look and behave exactly as the group on a historical painting.

• Adventure
• Family