The Mistery of the Hidden House

Constable Goon's nephew Ern, the same age as the young detectives, comes for the holidays, but Goon strictly forbids the children to communicate. And then, for the sake of a joke, the guys invent a non-existent story about a place where something suspicious is happening. Unlucky Ern swallows the bait, but, without knowing it, attacks the trail of a real crime!