Documentairy about the progressive theatre group 'Het Werkteater' at their home base on Kattengat 10 in Amsterdam.

A gang of city children is secretly practicing to enter a musical competition. All of them plunder their parents' supplies in order to build their own stage and amplifiers. Baffled by these unexplained thefts, the parents decide to hold a meeting as their suspicions turn to a group of camper folks living across from their flat. The tables are turned when the residents take a camping holiday of their own and end up being mistrusted by the locals as much as they themselves did their own neighbors. Meanwhile, the children's gang meets a rival group of kids who are planning to enter the same competition.

Three robbers who have just robbed a gas station flee into the zoo. But in their haste, they lose the note telling them where they hid the money. The note is found by two children who help take care of the animals in their spare time... This is the beginning of an exciting adventure, in which the children track down the crooks. In a wild chase through the zoo, the animals also make themselves heard, and the children receive help from an unexpected source!