In early 1970s Japan, a dramatic rise in violent crime, terrorist activities, and corruption has made it impossible for standard law enforcement to maintain public safety. Facing this crisis, the Japanese National Police Agency authorizes the creation of a secret, off-the-books counter-terrorist unit. This unit, designated Wild 7, is assembled not from model officers but from hardened criminals. Recruited from prison, its members are a motorcycle-riding squad of reformed convicts, including former Yakuza enforcers, violent street thugs, and petty criminals, all given a chance to earn their freedom by doing the jobs that ordinary police cannot or will not touch.

The central figure of the team is Hiba Dairoku, the youngest member of Wild 7 and its de facto leader. A man with over a dozen criminal convictions for offenses ranging from assault to robbery, he is a brilliant tactician, a master of hand-to-hand combat, and a highly skilled mechanic and rider. Despite his cold and ruthless demeanor towards enemies, he possesses a strong sense of loyalty and a hidden sense of justice. He is joined by a motley crew of specialists. Hebopy (real name Ryuuji Tsuji) is a former student activist with superhuman strength and a calm, intellectual side. Other members include a disgraced former professional baseball pitcher who uses hypnosis as a weapon, and other experts in violence recruited from the nation's prisons and streets. They operate under the supervision of the National Police Agency, often clashing with traditional police who resent their brutal methods. Their primary adversary is a powerful and shadowy criminal syndicate known as the Black Spider, which has infiltrated politics and high society, making its members untouchable by conventional legal means.

The narrative follows the Wild 7 as they wage a secret war against the Black Spider and other high-level threats. The team uses their criminal expertise to outmaneuver their targets, relying on high-speed motorcycle tactics and lethal force, operating outside all legal constraints. One notable arc involves the team's female assistant, Eiko, who is captured by the Black Spider and brainwashed into becoming a spy. She is ordered to assassinate the Wild 7 and attacks them with a submachine gun. The team survives the assault and manages to deprogram her, turning her brainwashing back on the gang to set an ambush. Each mission pushes the boundaries of acceptable violence, operating in a grey area where the law has failed and only outlaws can restore order.

Despite being a popular success with television audiences, the live-action Wild 7 series was highly controversial for its graphic depiction of violence. The show was ultimately forced to end its run after a single season of 25 episodes, airing from October 1972 to March 1973 on NTV, due to concerns from broadcasters and public sentiment about the level of brutality being shown on television.