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.

Arale and her friends learn of a World Grand Prix being organised by the Radial Kingdom. The prize is marrying Princess Front (a dead ringer to Ms. Yamabuki) or 1 million dollars. Of course they decide to enter for the money. Not so for Dr. Mashirito; he is going for the princess and will stop at nothing to win! The princess though has her own plan, which involves Ms. Yamabuki, and that of course means even Dr. Slump decides to enter with his trusty Borobo. Let the race begin...

When local teacher Midori Yamabuki receives an emergency summons to her home planet it turns out to be a trap devised by galactic warlord Dr. Mashirito, and it's up to Dr. Senbei Norimaki and a group of students (including his robot daughter Arale) to venture into space to save her.