A spiral design spins. It's replaced by a spinning disk. These two continue in perfect alternation until the end: a spiral design, a disk. Each disk is labelled and can be read as it rotates. The messages, in French, feature puns and whimsical rhymes and alliteration. The final message comments on the spiral motif itself.

On a quest to find out what happened to his missing brother, a scientist, his nephew and their mountain guide discover a fantastic and dangerous lost world in the center of the earth.

Laura and Fabrizio have been meeting every summer in the forest by her parent's summer home. Fabrizio is a solitary boy with only his dog for company; Laura a sweet but unconfident child. This summer new aspects enter into their story as both are growing up. Laura is falling in love with Fabrizio, while he displays a new sexual awareness of her masked by his malice. Things develop further when they meet Sylvia who, unlike the innocent Laura, is confident and assertive. Fabrizio develops a fascination with her, eventually bribing Laura to fetch her to the forest to join them in play.