Nicholas leads a peaceful existence. He has parents who love him, a gang of terrific friends to play with, and no desire for anything to change. But one day, Nicholas overhears a conversation between his parents which leads him to believe that his mother is expecting a child. He panics and imagines the worst: a little brother! Nicolas’ parents will no longer have time for him. They might even abandon him in the forest like Little Tom Thumb. To escape this disastrous fate, Nicholas embarks on a huge campaign to make himself indispensable to his parents. But by trying too hard, he only accumulates blunder after blunder and provokes their anger. Desperate, he decides to change tactics. After all, it’s not up to him to leave. He was there first. The one that should disappear is the baby. Nicholas and his pals come up with all kinds of plans. Plans that lead them into increasingly zany misadventures. Unaware of the risks they are taking, the kids wreak havoc throughout the entire town. But right when they think they’ve found the solution, Nicholas sees a friend whose mother has just had a baby and who describes all the positive aspects of being a big brother. It doesn’t sound to bad at all to Nicolas. He runs home and tells his parents that he’s delighted to have a little brother. When they explain that there’s been a misunderstanding, he starts to cry and reproaches them for never wanting to make him happy. But one last surprise awaits our hero…