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.