Gu Yubai learns from his mother that he has a betrothed he has never met, living far away in Yuncheng. His first reaction is resistance and disbelief, and he wishes he could cancel the engagement immediately. However, when he reluctantly moves into the seaside guesthouse run by his betrothed, he falls in love at first sight with the sweet-smiling girl whose voice is soft and gentle. His plans shift from figuring out how to break off the engagement to dating before marriage and carefully winning her heart. A youthful romance born from a promise made by their grandparents quietly begins amid sea breezes and sunset skies. As it turns out, fate's red thread had already bound the two of them tightly together!