The new mayor of Kasukabe city, Mamoru Shizen, put great efforts into environmental protection, but actually he has an evil plan behind it. One day, Hiroshi and Misae drink a mysterious bottle that Shinchan has found from the riverside and they gradually transform into animals! The bottle is actually a drug that Shizen, the leader of “Save Keeping Beautiful Earth (SKBE)”, uses to change people into animals in order to halt the destruction of the environment. To save their parents, Shinchan and Himawari work with Kasukabe Defence Force and go to the headquarter of SKBE. Can they stop Shizen and save their families?