"Crayon Shin-chan: Arashi o Yobu Mōretsu! Otona Teikoku no Gyakushū" is a feature-length anime film centered around the mischievous yet endearing five-year-old Shinnosuke "Shin" Nohara. The story begins with Shin and his family encountering a mysterious organization known as the Otona Teikoku (Adult Empire), which seeks to eliminate all forms of childish behavior and impose a strict, adult-centric world order. The organization uses advanced technology to brainwash adults, turning them into rigid, humorless individuals who enforce their ideals.

Shin's parents, Hiroshi and Misae, fall victim to the Otona Teikoku's influence, becoming cold and authoritarian. Shin, along with his friends and younger sister Himawari, must navigate this transformed world where playfulness and imagination are outlawed. The children band together to resist the oppressive regime, using their creativity and resilience to challenge the Otona Teikoku's control. Along the way, they uncover the organization's origins and its leader, who harbors a deep-seated grudge against the innocence of childhood.

The narrative explores themes of individuality, the importance of play, and the clash between the carefree nature of childhood and the structured demands of adulthood. Shin's antics, though often chaotic, serve as a counterbalance to the Otona Teikoku's rigid ideology, highlighting the value of spontaneity and joy. The film blends humor, action, and heartfelt moments as Shin and his friends work to restore balance to their world, ultimately reminding both the characters and the audience of the enduring significance of childhood wonder.