Taking place in 1941, Love in a Fallen City centers on Pai, a young woman who has been ostracized by her family for divorcing her rich husband. A local match-maker, Mrs. Hsu, takes pity on Pai and decides to bring her to Hong Kong, under the guise of employing her as the Hsu's nanny, but in reality to introduce her to Fan. Pai and Fan seem to hit it off, but Fan's refusal to marry Pai soon sours things. However, as the Japanese begin to invade Hong Kong, the two begin to realize their true feelings for each other.