In the land of the pyramids, the Rainbow Prince turns everyone into pyramids! Can Anpanman find snow and water, the weakness of the Rainbow Prince, and stop him before it's too late?

Children are lured to Metropolis only to find that the renowned, mythical city may not be the happy-go-lucky utopia they'd thought it would be.

Senbei Norimaki finds the secret treasure named “Eye of Rainbow” of the legendary Nanaba Castle in the mountain. This treasure makes every dream come true. When the gang of Arale Norimaki and Gatchan tried to steal the treasure, Bisna, who is the descendant of Nanaba Kingdom, takes the treasure. Bisna wants to revive the devil and Nanaba Kingdom. Arale and her friends went towards the secret Nanaba Castle to get back the treasure.