Keiko and Toshiko are sisters who leave their mountain home, where their parents live in a hydroelectric plant company house to study in the city. They stay with their kind-hearted aunt and her jovial but heavy-drinking carpenter husband. Keiko, the 17-year-old eldest of five siblings, is gentle and responsible, while 14-year-old Toshiko is lively and childlike, affectionately called "Konchi."