A man pretending to be Madeline's uncle kidnaps her and plans to steal her inheritance.

In an old house in Paris, that was covered with vines, lived twelve little girls in two straight lines. They left the house at half past nine in two straight lines, in rain or shine. The smallest one was Madeline. At Miss Clavel's boarding school, Madeline is unlike the other girls. Rambunctious, adventurous and fearless, there is no feat she isn't unwilling to try. When her long-lost Uncle Horst comes to take her, Madeline is overjoyed at the prospect of having a family. But soon it becomes clear that "Uncle Horst" isn't what he seems and Miss Clavel and the 11 Little Girls must find a way to rescue Madeline from misery.