Su Yue is thirty-five, a powerhouse at an advertising agency, on the verge of a promotion and about to get married. But an accident on her birthday turns her body back to how it looked at eighteen. Her boyfriend dumps her, workplace rumors swirl, and her promotion is taken away.
Forced to return to campus and “live her youth over again,” she meets Lin Yu, a puppy-like underclassman ten years her junior. Everyone else sees her as just another student her age, but Lin Yu sees the maturity, composure, and sharpness she can’t hide.
She tries to draw a firm line between them, but with every steadfast choice he makes, he pulls her out of the belief that “I don’t deserve to be selfish anymore.” Outside doubts, her parents’ opposition, and the secret of her identity all threaten to explode like a ticking time bomb. But Lin Yu tells her, “You haven’t gone back to eighteen. You’ve finally been given the chance to live for yourself again.”
She gets a fresh start, builds a business, and turns her life around, while he makes “I fell hard for you” his answer for the rest of his life.