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...!

The man who hails from the future, Geiz, attacks Sougo! Tsukuyomi, a girl who also hails from the future, came to help out Sougo, but Sougo has absolutely no idea what's going on! A mysterious prophet named Woz is also starting to appear frequently before Sougo. The creature, Another Build also attacks. What could be the key to defeating this "Kamen Rider Build"? Sougo makes his way towards the Nascita Cafe to meet with Kiryu Sento...