While planting trees with a group of children, Barbie overhears the kids making fun of one little girl's tiny tree, so she tells them the story of Thumbelina -- a very tiny girl who made a big difference. Thumbelina is one of the tiny Twillerbees who live in fairy-like homes in magical harmony with nature. One day a spoiled young girl named Makena asks her daddy to transport an entire patch of flowers to her room. Thumbelina and her Twillerbee friends, who just happened to be hiding in the flowers, are uprooted from their homes and the field they love.
While at Makena's apartment in the city, Thumbelina learns that Makena's parents are building a factory and plan to destroy the very field where Thumbelina and the Twillerbees live. Thumbelina bravely reveals herself and tries to convince Makena to stop her parents, but Makena sees Thumbelina as nothing but a new and impressive toy for her to own. Poor Makena doesn't understand what friendship is about, but maybe if Thumbelina can help her see, she'll understand why helping the Twillerbees is the right thing to do.