Patrick's mum Margaret would rather he looked after the milkweed fields back home. He is not alone in his suffering, his best friend Marty is still a caterpillar and can't fly at all. However, the two friends have an ingenious plan: they want to fly along as stowaways in the leaf trailer for the milkweed supplies. This is pulled by Jennifer, who is hiding a secret from the other butterflies: she suffers from a terrible fear of heights and faints if she flies too high up. Nevertheless, she agrees to give the two friends safe passage to Mexico. The adventurous journey quickly presents the trio with major challenges. Whether it's vengeful finches, stormy weather or scarce resources - after this journey, nothing is the same for the butterflies as it was at the beginning.