One day, Shin-chan (voiced by Akiko Yajima) picked up a bottle of mysterious liquid on the riverbank, took it home and put it in the refrigerator. But Miya (voiced by Miki Narahashi) and Hiroshi (voiced by Keiji Fujiwara) drank it accidentally, and the next day they mutated into animals. Afterwards, a mysterious environmental organization SKBE kidnapped Shin-chan's family, and the leader was the head of Futaba Village, Yozen-sama (voiced by Hirokazu Yamadera). It turned out that Yozen-sama was a radical environmentalist who wanted to turn all humans who destroyed the environment into animals through a mysterious drug. The mysterious liquid that Shin-chan picked up was a drug that was still in the testing stage. Yozen-sama was going to use Miya and Hiroshi as experimental subjects for research. With the help of the mysterious woman Victoria (voiced by Yuko Goto), Shin-chan and his group successfully escaped. Together with the Kasugabe Defense Force, they were determined to crack Yozen-sama's conspiracy.