A Japanese woman named Kato Youki travels to Taiwan for a three-month stay following a breakup, with the intention of learning Chinese at a language school. During her time there, she has a fleeting romance with a man named Wu, who then proposes a 90-day contract for her to be his girlfriend, which she accepts. A stipulation of this agreement is that they must part ways after the 90 days. As they grow closer and develop a deeper understanding of each other, they both start to feel that their connection is genuine love, making them reluctant to adhere to the contract’s terms as the deadline looms. What ultimately becomes of their romantic journey?