Organized crime's "Protection" Boss Duke Slate decides it's time to acquire "the city's Chinatown district" and uses Low Sing's tong to handle his influence. Low Sing, a martial arts professional, instructs his craft to his gang using the actions of a caged Praying Mantis, analogizing its intricate moves to proper Kung-Fu application. After a kidnapping engineered by Low Sing, a challenge between Low Sing and Kato is inevitable.