Shin Ara does not believe in destiny. She believes in load-bearing walls, primary source evidence, and coffee made at the exact right temperature. So when she sprints for the last train on Line 5 and collides with a man whose amber eyes feel impossible and familiar at the same time, she files it under coincidence and goes home. Gu Serin has been waiting for two hundred years. He recognizes her immediately the soul he has loved across five lifetimes, returned in a new form. He does not tell her. He gives her time. He has learned that this particular soul does not accept claims she cannot verify herself. What follows is not a fairy tale. It is something more difficult and more real: two people building toward each other with full information, across a bond that is two centuries old and a relationship that is entirely new, in a city that remembers everything. The water remembers. And love remembers longer.