Retired couple Shūkichi and Tomi Hirayama live in Onomichi in western Japan with their daughter Kyōko, a primary school teacher. They have five adult children, four of whom are living. The couple travel to Tokyo to visit their son, daughter, and widowed daughter-in-law.

Their eldest son, Kōichi, is a physician who runs a small clinic in Tokyo's suburbs, and their eldest daughter, Shige, runs a hairdressing salon. Kōichi and Shige are both busy and do not have much time for their parents. Only their widowed daughter-in-law, Noriko, the wife of their middle son Shōji, who was missing in action and presumed dead during the Pacific War, goes out of her way to entertain them. She takes time from her busy office job to take Shūkichi and Tomi on a sightseeing tour of metropolitan Tokyo.

Feeling conflicted that they do not have time to entertain them, Kōichi and Shige pay for their parents to stay at a hot spring spa at Atami, but they return early because the nightlife disturbs their sleep. Tomi also has an unexplained dizzy spell. Upon returning, a frustrated Shige explains she sent them to Atami because she wanted to use their bedroom for a meeting; the elderly couple has to leave for the evening. Tomi goes to stay with Noriko, with whom she deepens their emotional bond, and advises her to remarry. Shūkichi, meanwhile, gets drunk with some old friends from Onomichi. The three men drunkenly ramble about their children and lives. A policeman brings Shūkichi and one of his friends to Shige's salon. Shige is outraged her father is lapsing into the alcoholic ways that overshadowed her childhood.

The couple remarks on how their children have changed, returning home earlier than planned, intending to see their younger son Keizō when the train stops in Osaka. However, Tomi suddenly becomes ill during the journey and they decide to disembark the train, staying till she feels better the next day. They return to Onomichi, and Tomi falls critically ill. Kōichi, Shige, and Noriko rush to Onomichi to see Tomi, who dies shortly afterwards. Keizō arrives too late, as he has been away on business.

After the funeral, Kōichi, Shige, and Keizō leave immediately; only Noriko remains. After they leave, Kyōko criticises her siblings over their selfishness toward their parents. She believes that Kōichi, Shige, and Keizō do not care how hard it will be for their father now that he has lost their mother. She is also upset at Shige for asking so quickly for Tomi's clothes as keepsakes. Noriko responds that while she understands Kyōko's disappointment, everyone has their own life and the growing chasm between parents and children is inevitable. She convinces Kyōko not to be too hard on her siblings because one day she will understand how hard it is to take time away from one's own life.

After Kyōko leaves for school, Noriko informs her father-in-law that she must return to Tokyo that afternoon. Shūkichi tells her that she has treated them better than their own children despite not being a blood relation. Noriko protests that she is selfish and has not always thought about her missing husband, and Shūkichi credits her self-assessment to humility. He gives her a watch from the late Tomi as a memento. Noriko cries and confesses her loneliness; Shūkichi encourages her to remarry as soon as possible, wanting her to be happy. Noriko travels from Onomichi back to Tokyo, contemplating the watch, while Shūkichi remains behind, resigned to the solitude he must endure.