In the JTBC drama "A Hundred Memories," the relationship between Ko Young-rae and Han Jae-pil, played by Kim Da-mi and Heo Nam-jun, is changing. The two have been friends for seven years, but recently they have been experiencing subtle emotional shifts. The drama centers on their story as they waver between friendship and love.

Young-rae currently works as a staff designer at a beauty salon, while Jae-pil is a busy intern doctor at a university hospital. Even after his shifts end, Jae-pil does not hesitate to seek out Young-rae, which raises suspicions among those around them. The salon staff joke about their relationship, saying, "Where is there friendship between a man and a woman?"

After work, Young-rae regularly cuts the hair of Jae-pil's father, Han Ki-bok. Despite his long battle with illness, Ki-bok shows a particularly gentle side when he is with Young-rae. Jae-pil's stepmother, Sung Man-ok, warns him, saying, "Don't keep such a pretty and kind girl just as a friend." Amid these surrounding views, Young-rae and Jae-pil take care of each other, and their relationship is developing beyond mere friendship.

Young-rae's feelings become complicated due to the overlap of the "Medical Students' Night" event and Rose Day. When Jae-pil asks Young-rae to be his partner for the event, she deeply contemplates its meaning. On the day of the event, Young-rae appears with radiant makeup and a pure white dress, and Jae-pil playfully asks, "Who are you?" Afterwards, he sincerely tells her, "You look really pretty," stirring her emotions once again.

When Young-rae injures her ankle, Jae-pil brings ice for a compress and carries her home. His care makes their relationship even more complicated. The subtle tension between Young-rae and Jae-pil intensifies, and at this moment, Jung-hyun returns from studying abroad. Jung-hyun provokes Jae-pil and reveals his feelings for Young-rae.

Jung-hyun tells Jae-pil, "If you took the kid, you should take good care of her," sparking a confrontation between them. Eventually, they get drunk at a drinking party and end up passing out side by side at Young-rae's house. During this time, Jae-pil firmly answers "No" to his friend Ma Sang-chul's question, acknowledging his true feelings for the first time.

Young-rae and Jae-pil have now become too close to be called just friends, yet too awkward to be lovers. Their relationship holds complex emotions where excitement blooms within familiarity. The drama explores the boundary between friendship and love through the emotional changes of these two.