In British Hong Kong in 1962, Shanghai expatriates Chow Mo-wan, a journalist, and Su Li-shen, a secretary at a shipping company, rent adjacent rooms in an apartment. Each has a spouse who works and often leaves them alone on overtime shifts. Due to the friendly but overbearing presence of a Shanghainese landlady, Mrs. Suen, and their bustling, mahjong-playing neighbours, Chow and Su often find themselves alone in their rooms. Although they initially are only friendly to one another as need be, they begin to grow closer as they realize that their spouses are sleeping together.