Lin Xi, a surgeon, unexpectedly travels back to ancient times and becomes bound to a life-prolonging system. She must complete various missions to extend her own lifespan. Through a twist of fate, she returns to the Marquis's residence under the identity of Murong Zhiheng, the legitimate daughter of the Marquis. Faced with complicated relationships within the household and the constraints of an arranged marriage, she calmly overcomes one crisis after another with her exceptional medical skills and clear-headed intelligence. She also becomes entangled in numerous encounters with the mysterious Nine Divisions. As she searches for the truth about her origins, she gradually takes control of her own destiny.