Yeo-Reum Lee, a university student, unexpectedly reunites with her first love, Su-Yeong Ji, and his fiancée, Han-Gyeong Bae, the owner of the café where she works. Their relationship began in high school when Yeo-Reum's mother worked as a housekeeper at Su-Yeong's family home. After years of heartbreak, they meet again, but this time, Su-Yeong unknowingly drinks a potion that makes him fall in love with Yeo-Reum. With the potion's effects lasting one year, will their love become real, or will it fade once the potion wears off?

(Source: WEBTOON)