Y/N, a quiet museum archivist, discovers a box of forgotten love letters. A visiting researcher, Katsuki Bakugou, arrives to help restore them, and together they piece together a romance that history never allowed to bloom. As they work side by side, their own connection mirrors the letters—gentle, hesitant, full of longing. They share coffee over dusty manuscripts, walk home together in the rain, and slowly become the person the other confides in. When the final letter reveals a promise never fulfilled, Y/N realizes they want to write a different ending for themselves… with the researcher.