An expedition in the South Pacific lands on a tropical island where the natives worship the mysterious deity Gappa. An earthquake opens up an underground cavern and a baby reptile is discovered inside. The natives warn the foreigners to leave the hatching alone, but they don't listen and take it back to a zoo in Japan. Soon after, moma and papa Gappa start smashing Tokyo looking for their kidnapped child.
Tajima is a private detective in charge of his own company, Detective Bureau 2-3. When warring criminal gangs go overboard by robbing U.S. military munitions, Tajima steps in to stop what the cops can't.
A college student takes over the family business in the field of organised crime.
