Crayon Shin-chan: Roar! Kasukabe Animal Kingdom

Mamoru Shizime is inaugurated as the new mayor of Kasukabe city and initiates environmental conservation efforts. His focus on protecting nature sets the stage for upcoming events, though it hints at underlying motives related to environmental issues. The story kicks off with a city seemingly committed to ecological improvement.

While cleaning the riverbank, Shinnosuke discovers a small, mysterious bottle containing a light green liquid. Curious, he takes the bottle home, unaware of its significance. This small act triggers the chain of events leading to the transformation and chaos that follows.

That night, Hiroshi and Misae accidentally drink the mysterious green liquid. Over time, they begin to transform into animals—Hiroshi into a rooster and Misae into a leopardess—causing concern and confusion within the family. Their transformations mark the start of the larger environmental experiment.

Shinnosuke's friends from the Kasukabe Defense Force arrive to check on him and his family. They encounter a mysterious group led by Bunbetsu attempting to capture them. Despite their efforts, they manage to escape, setting the stage for the confrontation with the antagonist.

Shinnosuke and his friends seek help from Victoria, who agrees to assist them. However, they are eventually caught after Hiroshi, transformed into a rooster, leads the enemy to a trap. Their capture intensifies the conflict with Mamoru Shizime and SKBE.

The group is brought before Mamoru Shizime, revealing his secret role as the leader of SKBE. He is executing the 'Human Animalization Plan' to prevent environmental destruction by turning humans into animals, erasing their memories forever. The plan is central to the story's conflict and moral dilemma.

After escaping from the base, the team follows Bunbetsu to an underground forest with a hidden base. Using animal powers, they try to overcome henchmen, but their efforts are thwarted when Shinnosuke is captured and found confronting his transformed parents.

The final showdown occurs at Kasukabe's underground base. Mamoru, now in a Chimera form, and Shinnosuke, transformed into an elephant, engage in a fierce battle. Himawari, as a polar bear, and Victoria intervene, reversing the chaos and destruction once the base is destroyed.

Victoria reveals herself as Yoshiko Shizime, Mamoru's wife, explaining his radical plan stemmed from despair over humanity's neglect of nature. Mamoru smashes the animalization drink to save his wife, leading to reconciliation. Their love and sacrifice help restore balance.

With the destruction of the base and Mamoru’s sacrifice, all animalized humans, including Hiroshi, Misae, and the others, revert to their original human states. Harmony is restored in Kasukabe, and Hiroshi becomes more environmentally conscious, returning to everyday life.