Deputy Officer of the United Nations Alliance, Simon Marcus, who aims to conquer the world with the terrorist organization Downfall along with the mad scientist Keiji Uraga, attack the Kamen Riders with overwhelming strength. It is only on Kamen Rider Grease that the enemy's abilities did not work. In order to defeat this new enemy and rescue Misora, Kazumi Sawatari must create a new item ... but it is told that it requires the life of his friends, the Three Crows. The ultimate decision must be made.

Kamen Rider Build NEW WORLD: Kamen Rider Cross-Z is a post-series V-Cinema film of Kamen Rider Build. It will focus on the character of Ryuga Banjo, Kamen Rider Cross-Z, along with Kamen Rider Prime Rogue. It was announced immediately following the broadcast of the final episode of Kamen Rider Build. The film will have a limited theatrical release in Japanese theaters before its home video release. This is the last Kamen Rider movie to be released in the Heisei era.

This gripping examination of the empty moral values and mindless violence of three bored preteens is depicted without judgment and without sensationalism. The leader is Marty, a hyperactive boy with a natural talent for violence and destruction. One day he is bored and decides to rob a local house beside the railroad tracks. He enlists the aid of two friends and they end up holding a woman and her wheel-chair bound husband hostage while they callously destroy their home.