A young Kamen Rider fan is granted his wish of seeing Riders in person, initiating the ultimate Japanese superhero crossover meta film. The third and final installment of the Heisei Generations series finds Kamen Rider Zi-O and Kamen Rider Build joining forces with all of the other Heisei Generation Riders to reverse the damages of an evil Time Jacker named Tid, and save their legacy. Are Kamen Riders real? Will you believe?

The Quartzers, calling themselves the Wardens of Time, appear after Sougo Tokiwa has collected all of the Heisei Era Ride Watches. A grand conspiracy behind the birth of the King of Time becomes ever clearer...