Dr. Slump Movie 04: Arale-chan Hoyoyo! Nanaba Shiro no Hihou  

Dr. Slump and Arale-chan: Hoyoyo! The Treasure of Nanaba Castle, Ｄｒ．スランプ アラレちゃん ほよよ！ナナバ城の秘宝, Dr. Slump Movie 4: Arale-chan Hoyoyo! Nanaba Shiro no Hihou, Dr. Slump and Arale-chan: Hoyoyo! The Treasure of Nanaba Castle, Ｄｒ．スランプ アラレちゃん ほよよ！ナナバ城の秘宝

Dr. Slump discovered a legendary treasure called "Eye of Rainbow" hidden in Nanaba Castle, which has the power to make all dreams come true. However, when a group of robbers led by Arale and Ga-chan attempted to steal it, Bisna, who is a descendant of Nanaba Kingdom, took possession of the treasure. Bisna's goal was to revive the devil and restore his kingdom. In response, Arale and her friends embarked on a journey to retrieve the treasure from the secret Nanaba Castle.