In 1960s Hong Kong, Chow Mo-wan, a journalist, and Su Li-zhen, a secretary, become next-door neighbors in a crowded apartment building. Both are married, but their spouses are often away on business trips. Drawn together by their shared loneliness and the absence of their respective partners, Chow and Su bond over their common interests in food, games, and serialized martial arts novels.

As their friendship deepens, they cannot ignore the striking similarities in their spouses' behavior. Suspicions arise, and they come to the painful realization that their partners are having an affair with each other. Devastated yet bound by convention, they grapple with their emotions and societal norms, seeking solace in their growing, yet platonic, companionship. As they spend more time together, they agree never to behave like their cheating spouses, but the intimate connection they share becomes increasingly complicated.