Kingdom 2068 (キングダム２０６８ Kingudamu Nisen-rokujūhachi) is the first episode of Kamen Rider Zi-O and the first part of the Kamen Rider Build tribute arc. Being so, it features the return of Sento Kiryu and Ryuga Banjo as portrayed by Atsuhiro Inukai and Eiji Akaso respectively. Geiz's GhostArmor makes a brief appearance at the end of this episode. This episode is accompanied by the first episode of Kamen Rider Zi-O: Supplementary Plan web series, Mystery of Naming.
Sougo Tokiwa seems like an ordinary high school student, but one thing he has different is that he has dreams of becoming a king! One day, a mysterious young man appeared before him with a prophecy. "Congratulations! Today is a special day for you..." As Sougo is told these words, a giant red robot suddenly appears before him! This robot was a time machine, and Sougo was thrust across various timelines! In the year 2000, the battle of the Heisei Rider's fate, and Sougo's fate in his own birth year, is about to begin...!