Oliver B. Bumble finds an egg that, it turns out, has a cute little dragon in it. However, this dragon grows huge each time it gets excited or upset. As this causes a lot of problems, Bumble has to face a difficult dilemma.

After lengthy discussions with Willy Vandersteen, the artist of the comic strip, this series was put into production in 1973. This happened in collaboration with the Flemish actor and producer Wies Andersen. Instead of adaptations of the existing comics, six new stories were chosen. The puppets were given multiple facial expressions and the sets and props were made based on detailed designs by Studio Vandersteen. Lambik always acts as narrator. A striking difference with the comics is that Jerom's doll now has its eyes open.