Detective Kouichi Todome head of the elite Kerberos police squad escapes after the unit is marked for destruction by the government. Three years later, Inui, a member of the squad, is released from prison with one goal: to find his former master. But the trail to Todome is a twisted one, and when Inui finally finds Todome, he realizes that instead of following his own path, Todome was following the orders of another.
In the film, the Crisis Empire devise a plan to defeat Kohtaro Minami by reverting him back to his old form of Kamen Rider Black and sending out several revived monsters after him. However, Kamen Rider Black is assisted by another RX, who used a time warp to help his past self. The two are joined by RX's alternate forms of Robo Rider and Bio Rider and the four Kamen Riders combine their powers to defeat the revived monsters.
During World War II, the Japanese military established a secret underground laboratory in Tokyo. Three Olympic-level athletes were selected to undergo a process that would turn them into Jinra-go, superhuman armored soldiers. By March 1945, one of the soldiers had been completely transformed into the half man/half machine ultimate soldier called Mikadroid. But American B-29s firebomb the city and, while the two super soldiers manage to escape, Mikadroid and the lab are apparently destroyed. 45 years pass, Tokyo is rebuilt, and old secrets are forgotten. The site is now home to a complex that includes the Discoclub Layla. The disco’s patrons dance late into the night, unaware that a faulty basement generator has reactivated Mikadroid and the cyborg now prowls the basement levels, killing anyone in its path...