A physicist named Tetsuo Okita discovers a new mineral called "Satanium," which is more powerful than uranium and emits destructive effects to anyone exposed to it. However, Destron abducts Okita in hopes of finding the source of Satanium and collecting more of it to expedite their run for global domination. Kamen Rider V3 must act fast in rescuing Professor Okita and preventing Destron from collecting more of the deadly mineral.
The Shocker Organization sends two of its Inhumanoids to destroy an atomic plant, but their plan is foiled by an invisible barrier that surrounds the complex. Because of this, they abduct a top soccer player and convert him into Tokageron, a lizard Inhumanoid capable of kicking a 5 kg bomb to destroy the plant's barrier. Kamen Rider must once again combat the Shocker and prevent them from destroying the atomic plant.
Takeshi Hongo and FBI agent Kazuya Taki fake their deaths when they are attacked by Shocker soldiers during a motocross race. They disguise themselves as Shocker soldiers and infiltrate the main headquarters, but it doesn't take too long for Ambassador Hell to find their whereabouts and trap them. Before he detonates a bomb within the base, Ambassador Hell tells Kamen Rider #1 and Taki that Shocker is preparing a giant laser capable of destroying cities. Our two heroes must escape from the base's self-destruction and stop Shocker from arming their latest weapon. Not only that, they must rescue Tachibana and the racing club, who have been abducted by Shocker's minions.
During a battle against Destron's forces, Shiro Kazami helps a priest who has been attacked by the evil organization's kaijin Hasami-Jaguar. Little does he know that the church where the priest resides is a front for a Destron hideout. After finding out the organization's latest motive, Kamen Rider V3, along with the Double Riders, must stop Destron from detonating a nuclear bomb in Tokyo.
Professor Daidōji has developed a gravity machine called the GX Device. Unfortunately, Shocker wants it; so they attack the professor and destroy his laboratory, but come home empty-handed. Shocker's agents find out that the plans for the GX Device are with Daidōji's daughter, who is celebrating her birthday. Now the Kamen Riders, along with FBI agent Kazuya Taki, must protect Daidōji's daughter and prevent Shocker from obtaining the plans.