Yeon Tae-seo heads to the countryside with his younger brother to stay with their grandparents. There, he meets Mo Eun-a and the two form a special bond.

Tae-seo and Eun-a's relationship continues to blossom, progressing from romance to intimacy. But adulthood soon separates them, testing their connection.

From school to relationships and work, Tae-seo struggles to juggle his responsibilities. Meanwhile, Eun-a’s career begins to reshape her life.

Ten years later, Tae-seo and Eun-a live completely different lives. One day, they cross paths again by chance — stirring old feelings.

Eun-a and Tae-seo slowly settle back into their rekindled rhythm. Meanwhile, they both navigate challenging personal and family issues.

Eun-a and Tae-seo slowly settle back into their rekindled rhythm. Meanwhile, they both navigate challenging personal and family issues.

Despite help from Bae Seong-chan, Eun-a struggles to find her place in the world. Tae-seo deals with unease as he confronts his family’s health issues.

Eun-a makes a decision that forces her and Tae-seo apart again. Soon after, a major misunderstanding leaves him heartbroken and betrayed.

Before long, Tae-seo's life returns to how it was before he reunited with Eun-a. But the question of why they broke up still lingers in his mind.

Eun-a decides where she will go, while Tae-seo decides how to say goodbye. Will their love endure -- even until the very last moment?