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.

Episodes 5 and 6 of Return of Ultraman show, screened at Toho Champion Festival.

A theatrical release of The Return of Ultraman episodes 13-14. It was released on December 12, 1971 as part of the Toho Champion Festival along with Godzilla, Mothra, King Ghidorah: Earth's Greatest Battle (edited from Ghidorah, the Three-Headed Monster) and shorter versions of The Adventures of Hutch the Honeybee, and The Little Match Girl.

A theatrical release of Return of Ultraman episode 29 as part of the Spring Toho Champion Festival along with other films like Godzilla vs. Gigan, The Adventures of Hutch the Honeybee, Mirrorman, and Mock the Oak Tree.