Ye Zhen suffers from pluviophobia—a rare condition where every time it rains, her memories reset to one year ago, back to the day she made a promise with a certain man. To uncover the truth behind her fragmented memories, she becomes entangled with Jiang An, the mysterious owner of a bookstore. Cold, distant, and full of lies and secrets, Jiang An nevertheless seems to watch over Ye Zhen at every moment. His familiar face unsettles her even more—why does he look so much like someone she once knew? But who is he, really?