In the southern country of Banana island, the energetic princess and his humble servant Banna invite Anpanman and his friends to their biggest festival "Banana Matsuri". But when they arrive a stormy and cold day bestows the island and withers all the Banana crop. While searching for the cause on the Banana Mountain a water monster appears that threatens to take back the island to the water world.

In the southern country of Banana island, the energetic princess and his humble servant Banna invite Anpanman and his friends to their biggest festival "Banana Matsuri". But when they arrive a stormy and cold day bestows the island and withers all the Banana crop. While searching for the cause on the Banana Mountain a water monster appears that threatens to take back the island to the water world. With the help of Banna, can Anpanman and his friends rescue the island from this crisis?