In early 1970s Japan, rising crime and terrorist activity have overwhelmed conventional law enforcement, pushing the government to consider extreme measures. The National Police Agency authorizes the formation of a secret, off-the-books motorcycle unit with a shocking premise: seven hardened criminals and ex-convicts will be granted immunity and the authority to kill in order to fight the criminals the regular police cannot touch.

The story follows this clandestine team, designated the Wild 7. Operating from a hidden headquarters, they are led by their police commander, Choppa Masaru, a former elite bureaucrat who believes that villains who evade the law deserve execution. His field commander is the young but fearsome Hiba Dairoku, a charismatic and ruthless leader with a staggering thirteen criminal convictions including robbery and assault. He is joined by a motley crew of outlaws, each contributing a unique brand of expertise. The team includes Heboppy, a former activist student with superhuman strength; Happi, a disgraced professional baseball pitcher who specializes in hypnosis; Ryokoku, an explosives expert; Oyabun, a former Yakuza leader; and Sekai, a former circus acrobat who handles acrobatic riding.

In the 1972 live-action television series, this team of convicted felons is assembled to specifically dismantle the Black Spider, a global criminal organization bent on world domination. Unleashed on the streets of Japan, the Wild 7 operates outside the bounds of legal procedure, using high-speed motorcycles and heavy firepower to raid hideouts, assassinate crime bosses, and eliminate threats with extreme prejudice. Their existence is a dark secret, and their methods are brutal, operating on the principle that the ends of public safety justify the use of any means.

The narrative arc of the original series is notable not only for its on-screen violence but also for the real-world controversy it generated. While the show was popular with audiences and achieved viewership ratings exceeding twenty percent, its graphic content drew significant concern. The depiction of anti-heroes sanctioned to execute suspects was considered highly controversial for the era. As a result, despite its success, the live-action series was forced to end after just 25 episodes, cancelled due to fears over the level of violence being broadcast on television.