Dunkum and his friends are in for the surprise of their lives! Dunkum loves mysteries. And when he digs for buried treasure, he uncovers one--in a mudhole! A locked box, covered in squishy mud. The discovery turns out to be a time capsule, buried many years ago. Curious, the Cul-de-sac Kids search their muddy prize for clues. Who buried the time capsule--and why?