Nicolas leads a peaceful existence. His parents love him, he's got a gang of great friends with whom he has a lot of fun, and he has no desire that anything should change...

But one day, Nicolas overhears a conversation between his parents that leads him to believe that his mother is pregnant. He panics and imagines the worst: soon a little brother will be there who will take up so much space that his parents will no longer have time to take care of him. They'll even go so far as to abandon him in the woods like Tom Thumb...