Zone Fighter, known in Japan as Ryūsei Ningen Zone, is a tokusatsu science fiction superhero television series. Produced by Toho Company Ltd., the show aired on Nippon Television from April 2 to September 24, 1973, with a total of 26 episodes, it was cancelled due to the oil crisis of 1973. This was Toho's answer to not only the popular Ultra Series, but the Henshin Hero phenomenon started by shows like Kamen Rider and Android Kikaider. The previous year, Toho had just made their successful first superhero show, Rainbowman. The series was also notable for its guest appearance by Toho's own Godzilla, as well as two other Toho monsters, King Ghidorah and Gigan. Supplementary materials published by Toho have confirmed Zone Fighter to be part of the Showa-era Godzilla series, taking place in between Godzilla vs. Megalon and Godzilla vs. Mechagodzilla.

A 20-year-old drifter and a precocious 16-year-old girl slowly form a bond in a small town haunted by its wartime past.

A trio of high school students, Ichiro, Hiroshi, and Reiko, try to give a demonstration against the suspension , but they are ignored by the students and embark on an unreliable journey.

A beautiful widow named Ruriko Omuta visits the Akechi residence and asks Kogoro Akechi to provide her with personal security. Just then, art dealer Yamano is shot dead right before Ruriko’s eyes. Sensing that there is more to the incident than meets the eye, Akechi sets out to investigate on his own. Meanwhile, back in her hometown of Nagasaki, a man named Shigeyuki Satomi—claiming to be a distant relative of Ruriko’s late husband—appears before her. Though Ruriko finds herself drawn to Satomi, she already has a lover named Yoshio Kawamura. What’s more, Kawamura has been involved in a terrible crime alongside Ruriko. Will Akechi be able to uncover their secret? And who is Satomi really?