とと姉ちゃん

In 1930 and as a young child, Tsuneko Kohashi lives at Enshu in Shizuoka Prefecture. She has a happy life with her parents and two younger sisters. Things change after her father dies from tuberculosis. Her father asked Tsuneko Kohashi to take care of the family in his place. Due to financial difficulties, her mother Kimiko decides to move the family to Tokyo where Tsuneko's grandmother lives.

Morishita Nao (Eguchi Noriko) shares an apartment with a female friend. Her roommate's younger brother Kotaro (Nakamura Kuniaki) leaves their family home and comes to stay with them. That evening, Nao witnesses Kotaro smelling her panties. The next day Nao begins acting provocatively towards him.