Kamen Rider Kabuto 20th: The One Who Inherits the Heavens: 20 years after the events of the series, humans and Worms are walking towards the path of coexistence. However, ZECT is secretly developing a new Masked Rider System. Yui Kagami, the son of Arata Kagami/Kamen Rider Gatack is qualified to use the new system. Arata Kagami also investigates a ZECT conspiracy all by himself, but a shadow of an unexpected person appears before him...!