The story begins with Eiji and Ankh engaged in an intense battle against a Yummy but accidentally allowing it to inhabit the body of a child named Naoki. Strangely, this child possesses memories from forty years ago (1971). When Koutaro arrives at the scene and meets Eiji, he reveals his ability to travel through time. Ankh, eager to obtain Core Medals before the GREEED awaken in the past, proposes traveling back forty years with Koutaro.

However, during the fight, Ankh accidentally drops a regular coin. In 1971, Shocker possesses Shocker Core Medals but lacks regular coins, which prevents them from creating the Shocker GREEED. When a Shocker combatant picks up Ankh's dropped coin, the Shocker GREEED is born. This marks a turning point as the powerful Shocker organization defeats Kamen Rider 1 and 2, brainwashing them into submission.

When Ankh and Eiji return to their original timeline, they find themselves in an era dominated by Shocker's rule. Determined to fix the altered history, Koutaro teams up with Ankh, while Eiji chooses to stay in his current timeline. Despite their efforts, one coin remains lost due to Ankh’s earlier actions. This coin is eventually found by a Shocker combatant and handed over to General Black.

Kamen Rider 1 and 2, who have not yet been brainwashed in the past, arrive to assist. However, due to General Black's schemes, the Shocker GREEED is created once again, thwarting their plans to restore history. As a result, the Den-Liner train is destroyed, leaving their mission in ruins and Shocker's dominance unchallenged.