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.
Unfortunately the movie Dr. Slump and Arale-chan: Hoyoyo! The Treasure of Nanaba Castle is not yet available on HBO Max.
| Directing | Hiroki Shibata | Director |
| Camera | Hisao Shirai | Director of Photography |
| Sound | Hidenori Arai | Sound Effects |
| Writing | Akira Toriyama | Original Series Creator |
| Visual Effects | Masami Suda | Key Animation |
| Visual Effects | Liu Teruhisa | Key Animation |
| Visual Effects | Tomekichi Takeuchi | Key Animation |
| Visual Effects | Masayuki Aoki | Key Animation |
| Visual Effects | Yukio Ebisawa | Key Animation |
| Visual Effects | Minoru Maeda | Key Animation |
| Art | Noriyoshi Doi | Background Designer |
