Twins, separated at birth, end up as a Hong Kong gangster and a New York concert pianist. When the pianist travels to Hong Kong for a concert, the two inevitably get mistaken for each other.

Jackie Chan
as Ma Yau (John Ma) / Bok Min (Boomer)

Maggie Cheung
as Barbara

Nina Li Chi
as Tong Sum (Tammy)

Teddy Robin
as Tarzan (Tyson)

James Wong Jim
as Mr. Ma

Sylvia Chang
as Mrs. Ma

Kirk Wong Chi-Keung
as Crazy Bull

David Chiang Da-Wei
as Sgt Chiang / Hotel Security

Mabel Cheung Yuen-Ting
as Tsui

Alfred Cheung Kin-Ting
as Boss Yung