Key Hunter is a prime-time Japanese television detective series. It aired on Saturday nights in the 9:00–9:56 p.m. time slot on the Tokyo Broadcasting System network from April 6, 1968 to April 7, 1973. There were a total of 262 episodes, and it was one of the most popular action dramas in Japan at the time. The story involved "Key Hunter", a special clandestine unit of the International Police, which endeavored to solve various crimes. "Key Hunter" was a unique TV show, which started out as a grand scale spy thriller never before seen in Japan. The episodes were individually themed on global crimes and political strife. The initial hardboiled theme later evolved to include intellectual elements involving action, and occasionally with comical elements as well. Tetsuro Tamba starred in the 1967 film You Only Live Twice as Japanese Secret Service agent Tiger Tanaka, an ally of James Bond. This role greatly influenced his image in "Key Hunter".

Jiro, a smooth-talking, womanizing bartender, flees from a Yakuza boss to Yanagase.