Empress Su Yumei unexpectedly loses ten years of memory, waking up remembering only her sister. She doesn't recognize the emperor, doesn't understand palace struggles, and single-mindedly wants to leave the palace and go home, only to find that her once most intimate sister has become an imperial noble consort, and her childhood sweetheart has also broken off their engagement with her. As old tokens of affection, family lies, and palace secrets gradually emerge, she begins to investigate why she entered the palace back then, and also re-evaluates true feelings among the emperor, old love, and sister, rewriting everyone's destiny.