Every year, the monarch butterflies embark on a great journey to overwinter in warm Mexico. The young butterfly Patrick desperately wants to go along, but has only one fully formed wing and therefore cannot fly. Together with his best friend, the clumsy caterpillar Marty, he is able to hide as a stowaway in the supply trailer, pulled by the sharp-tongued butterfly girl Jennifer, and thus join the journey after all. But even the so self-confident Jennifer struggles with a problem that she tries to keep secret from her crush: she suffers from a terrible fear of heights. The trio must not only face their own fears on the arduous journey, but also take on dangerous tornadoes, landscapes that have been built over by humans, and three vicious but not particularly clever finches. A great adventure begins, in the course of which Patrick and his friends learn: the things that connect us are more important than the differences that seem to separate us.