Nicolas leads an untroubled existence. He has parents who love him and a nice group of friends to have fun with, so he has no desire for things to change…

But one day, Nicolas overhears a conversation between his parents which leads him to believe that his mother is pregnant. He panics and fears the worst: soon, there’ll be a little brother who will occupy so much attention that his parents won’t have time for him, and he’ll end up being abandoned in the forest like Tom Thumb…

To escape this imagined fate, Nicolas launches a major charm offensive against his parents in order to make himself indispensable. But in trying to do too much, he makes a catalogue of errors and instead incurs their wrath. Desperate, he decides to change strategy. After all, it’s not he who should go. He was there first so, by rights, it’s the baby who should disappear…

Nicolas and his pals concoct all manner of plans to get rid of the baby, resulting in increasingly wacky adventures where the children, unaware of the risks they are running, wreak havoc throughout the town.