The first behind-the-scenes documentary in the film industry, from the making of a camera (Debrie) to studio shooting and directing, including animation techniques. Pierre Chenal meets André Rigal who executes, in his workshop, a series of freehand drawings. These sketches are then ground in a coffee grinder, from which a cartoon on film emerges. In Champigny, Alain Saint-Ogan and his host are working on Zig et Puce and developing Alfred the penguin's first steps. In Fontenay-sous-Bois, Ladislas Starewitch presents his future stars. Pierre Chenal described his film as follows: “I had designed to shoot a documentary in which I would show how a film is made in order, at the same time, to learn it myself. "

The Bug Trainer explores Starewitch’s creative ideas and concepts of his work, along with opinions from film critics and other animation directors to help us understand why he is considered one of the greatest creators of the animation world.