In Hong Kong, Circa 1940s, World War II, private detective Yoyo and friend Inspector Teddy Robin join a resistance group during the Japanese occupation. They aim to steal back the formula to the atomic bomb from a war traitor and transfer it to an American before the formula ends up in the Japanese emperor's hands.

George Lam Tsz-Cheungas Yoyo
Teddy Robinas Inspector Teddy Robin
Brigitte Linas Bridget
Paul Chun Puias Fat Chicken - Commissioner of Police
Brenda Lo Yip-Meias Dumplings
Tsui Harkas Japanese Ambassador
Anders Nelssonas The American
Joe Junioras Sam/Joe
Kit-wah Leungas Yoyo's secretary
Yip Ha-Leias Fixes Yoyo's telephone