The film opens with a Saiyan Space pod flying through space and crash-landing on Earth out of which a wounded Saiyan crawls out: Broly, the Legendary Super Saiyan. The wounded Broly shouts out in frustation and turns into normal form. The place soon freezes, trapping him in it and he falls into a coma.

Two sisters move to the country with their father in order to be closer to their hospitalized mother, and discover the surrounding trees are inhabited by Totoros, magical spirits of the forest. When the youngest runs away from home, the older sister seeks help from the spirits to find her.