Parents from around the world hold a congress to discuss how to deal with their misbehaving children. All parents come together — only one set is missing, the parents of Sylvester, the best boy in the world. The congress decides to go see him so he can lead the other children by example. Sylvester is truly an exceptional child, but his "being good at all times and under all circumstances" somewhat gets out of hand.
Unfortunately the movie The Boy Who Became a Cupboard is not yet available on HBO Max.
| Directing | Jaroslav Doubrava | Director |
| Writing | Jaroslav Doubrava | Screenplay |
| Writing | Miloš Macourek | Idea |
| Crew | Jindřich Vodička | Dramaturgy |
| Visual Effects | Jaroslav Doubrava | Animation |
| Visual Effects | Cilka Dvořáková | Animation |
| Visual Effects | Jiří Plass | Animation |
| Visual Effects | Jarmila Doubravová | Animation |
| Visual Effects | Pavla Müllerová | Animation |
| Visual Effects | Judita Michlová | Animation |
| Art | Adolf Born | Graphic Designer |
| Sound | Ferdinand Havlík | Music |
| Sound | Jan Kacian | Sound |
| Editing | Jiřina Pěčová | Editor |
| Production | Jiří Soják | Production Manager |
| Camera | Jaroslava Zimová | Director of Photography |
