A short-tempered, violent criminal named the "White Tiger" is on the run from the police and joins a theater troupe to hide out, killing anyone who angers him or who suspects his identity. One person he unsuccessfully tries to kill several times is a cowardly laundry man named "Mousy" who manages to escape by fleeing. When a very close friend of Mousy's is killed by the White Tiger, Mousy overcomes his cowardliness enough to seek revenge.
In a scene early on in the movie Mousy is washing the laundry with his bossy sister. After complaining about the repetitiveness of laundry work, his sister scolds him and demands he wash the clothes in the "family way." This leads to a scene with Yuen Biao's character flipping the clothes around with his hands and wringing them out with powerful squeezing from this index finger and middle finger. These abilities turn out to be related to kung-fu methods, as Mousy eventually uses the same laundry method to defeat "White Tiger."