Joo Yeokyung, the heiress of a corporate empire and the youngest executive in a leading domestic conglomerate, carries an enigmatic secret despite her seemingly perfect life. Nestled within her flawless façade lies an astonishing truth - her age changes with the falling rain.

Bound by the confines of a genetic condition passed down through generations, Yeokyung has navigated a life burdened with limitations. The weight of her inherited syndrome has made her existence a delicate dance.

As a prolonged monsoon season blankets the city, Yeokyung's life takes an unexpected turn. One fateful day, a mysterious man steps into her world, becoming the catalyst for a series of events that will unravel the layers of secrecy she has meticulously maintained. In the face of this unforeseen connection, Yeokyung must confront her hidden truths, and both she and the stranger must navigate the complexities of love, identity, and the uncharted waters of a life touched by a rain-kissed secret.