In 1970s Hong Kong, rapacious landlords try to evict 72 tenants but sworn brothers Ha Kung and Shek Kin help the group of 72 defeat the landlord and landlady and coincidentally rescue Pinky from a planned forced marriage. When both sworn brothers fall for Pinky and propose to her, she flips a coin heads or tails, they both cheated during the toss but Ha wins her hand in marriage.

The sworn brothers become sworn enemies and Sheks hatred fuels intense rivalry against Ha in business dealings ranging from the manufacture of plastic flowers to the selling of stinky bean curd. Even after 40 years they continue to clash and in 2010 they are in keen competition selling electronics appliances in Sai Yeung Choi Street, Mongkok, the busiest street in the city and still home to the 72 tenants.

This film used the 1973 Shaw Brothers film, The House of 72 Tenants as the blueprint. However, this story is a new creation, of which only some roles identical. This is the first film to introduce the new 2010 Shaw opening theme with a shortened version of the original fanfare.