Akiko Sugiyama (Ineko Arima) is a college student learning English shorthand. Her elder sister Takako (Setsuko Hara), running away from an unhappy marriage, has returned home to stay with Akiko and their father Shukichi (Chishū Ryū) in Tokyo, together with her toddler girl. Shukichi works in a bank in Tokyo. Akiko has a relationship with her college boyfriend Kenji (Masami Taura), which results in an unwanted pregnancy. Later, Akiko has an abortion, after an encounter in which she realizes that her boyfriend does not love her. While going to a mahjong parlour to look for Kenji, Akiko comes across its proprietress Kisako (Isuzu Yamada), who seems to know a lot about her family. Back at home, Takako hears about Kisako from Akiko, and pieces together the fact that she is their long-lost mother. Takako visits the parlour to ask Kisako not to reveal to Akiko who she really is – but the plan backfires. Akiko learns of her visit and goes to confront Takako. Takako then discloses to her that Kisako is their mother, who ran away with another man when Akiko was still a toddler. Shaken, Akiko goes to confront Kisako to ask if she is the daughter of her father. She leaves in a huff, upset by Kisako abandoning her as a child, then goes to a Chinese noodle shop for some sake. Her boyfriend Kenji enters, and the two have an argument. Akiko leaves angrily, and is hit by a train at an intersection just outside the shop. Akiko is badly injured and she expresses the wish to live and start life over again in the presence of her father and sister. In the next scene however, in one of Ozu's famous ellipses, a bitter Takako goes to visit her mother to tell her the news of Akiko's death. Kisako is distraught, and agrees with her husband that she will leave Tokyo for his new job in Hokkaido. Just prior to their departure, she goes to the Sugiyamas to offer her condolences, and to tell Takako of her decision. Takako does not go to send her off at the railway station.