Plot
Following her divorce, Yoon-hee (Kim Hee-ae) and her teenage daughter Sae-bom (Kim So-hye) live together in the Korean countryside. Sae-bom discovers a romantic letter written to her mother by Jun (Yūko Nakamura), a Korean-Japanese woman who went to school with Yoon-hee in her youth. Though the relationship is long in the past and remains a deep secret, Sae-bom recognises her mother's unrelenting loneliness and hopes to comfort her.
Upon graduating high school, Sae-bom insists she and her mother take a celebratory holiday to Japan, knowing Jun resides in the quiet and snowy village of Otaru. There, Yoon-hee immediately seeks out Jun's home but is unable to approach her. Soon after, Yoon-hee reveals that she knows Sae-bom is aware an "old friend" lives in the village but admits they haven't reconnected.
In the local cafe, Sae-bom meets Jun's aunt Masako and asks her to tell Jun to come to the cafe the next morning. At home, Jun confesses to her aunt that she and Yoon-hee are together in her dreams. Meanwhile, Yoon-hee discovers Sae-bom's boyfriend Kyung-soo has secretly come along to Otaru.
The next day, Sae-bom meets Jun and lies that her mother is not with her. She coordinates for Jun to "meet her for dinner" and Yoon-hee to "pick her up" at the same time and location. Saebom's plan works: the two women meet, overwhelmed by emotion, and walk along the canal together.
A final letter from Yoon-hee to Jun is revealed, in which she shares that she confessed her love for Jun to her parents, who sent her to a mental hospital. Later, she married a man set up for her by her brother, who she resents. On her wedding day, she thought of Jun; when strangers wish her happiness, she thinks of Jun. She concludes the two were never wrong for their love and should feel no shame.
Yoon-hee and Sae-bom move to Seoul, where Sae-bom attends university and Yoon-hee uses her newfound courage to open a restaurant.
