Once Upon a Love (Chinese: 原來愛·就是甜蜜) is a Taiwanese idol romance drama television series written by Yang Yi Xun、Jing Ru and Hui Fen and is directed by Lin Qing Zhen.

A decade ago when Li Jin Yang/John Lee (Sunny Wang) was still a high school student, because of what Tian Ru Mi (Cheryl Yang) said - who was then the crowned "Rose Princess", inspired him to become a fashion designer.

However, things did not turn out as good for Ru Mi who once won the "Rose Princess Pageant" is now a tour guide and also a single mother with an eleven-year-old son.

After receiving a phone call, Jin Yang was informed that his grandmother (Mei Fang) was sick and wanted to bring his girlfriend Rebecca (Katherine Wang) back to Taiwan with him to meet his family.

After Jin Yang unknowingly helped Ru Mi to complete a new design template for the bus's exterior that was drawn by her son, Tian Yi Xiang, Jin Yang and Ru Mi meet again after ten years.