[1] Famous professor Daidoji completed his innovative GX device, which would allow its owner to control gravity.

Suddenly, Daidoji, together with his assistant, is attacked by Doctor Death from an evil secret organization called Shocker.

Using a visual trick, a monster learns that a formula needed to activate the device is with Daidoji's daughter.

When considering potential future actions, Doctor Death calls the Tachibana Racing Club and offers to exchange Daidoji for his daughter.

After the exchange in the Hell Valley, Doctor Death reveals that all this time it was his trick and he has no intention of letting Kamen Rider 2, who accompanied the professor, leave alive.