Kamen Rider

Takeshi Hongo, a young scientist and a racing prodigy, is abducted and his body surgically remodeled by Shocker, an evil secret society plotting for global domination.

Hongo wins the championship and the model who brings him his bouquet bares her fangs and attacks; Hongo investigates the woman's home, and finds it has been transformed into a lab.

Shocker tests their mysterious Scorpion Man by releasing their slave workers and telling them that they can have their freedom if they can escape within 10 minutes.

At an amusement park's botanical gardens people start disappearing; Kenji's older sister Yukie gets abducted, and he tries to tell someone that his sister was attacked by a giant Sarracenian.

While a series of strange earthquakes are going on, Hongo is contacted by his childhood friend and seismologist, Amemiya Chikako.

Former navy lieutenant-commander Sunada is attacked by the Chameleon Man; his aim is to get secrets relating to a Nazi treasure concealed inside a submarine model.