This novel focuses on the life choices made by two women who meet for the first time at age 35 and discover that they had attended the same university's Faculty of Letters together. The odd-numbered chapters track events in the two women's present-day lives from the perspective of Sayoko, while the even-numbered chapters look through Aoi's eyes at recollections of her high-school days.
Sayoko worked at a film distribution company after college, but then quit her job to marry and start a family. With her daughter now three, she decides she wants to reenter the workplace; the position she finds is at a small travel agency where Aoi is the boss. Business is not going well, though, and Aoi taps Sayoko to head up a new housecleaning side business. Sayoko puts her nose to the grindstone while bearing up under criticism from her mother-in-law and her own feelings that she might be doing the wrong thing for her daughter.
Two decades earlier in the story, Aoi's family has moved from Yokohama to the small regional city where her mother grew up in order to give her a fresh start, away from the bullying she suffered in middle school. At the girls' high school she enters there, she makes her first friend, Nanako. During their junior-year summer break, Aoi and Nanako get jobs at a seaside inn, with room and board as part of the pay. There they learn the joy of work. When the summer ends and they leave the inn, Nanako announces that she doesn't want to go home; the friends wander from place to place for a while, their trip culminating in an unsuccessful attempt at dual suicide. This puts an end to their relationship. Aoi goes on to university and launches her company after graduating.
As the book wraps up, the travel company's handful of employees clash with their employer and quit, leaving the firm effectively dead in the water. Aoi almost loses Sayoko as well, but in the end she returns, and the two vow to work together to bring the company back.