In ancient times, Emperor Zhaoming selflessly sacrificed himself to battle the divine realm, striving to save his people. Upon his fall, his beloved, Hun Dunzhu, risked everything to rescue a fragment of his soul, initiating an eternal cycle of reincarnation. Millennia later, Zhaoming is reborn as Xie Xuechen, the esteemed leader of the Celestial Alliance, while Hun Dunzhu returns as Mu Xuanling, the revered saintess of the Dark Domain. Reunited in the mortal world, they have no memory of their past lives and stand as sworn enemies embodying good and evil. When Mu Xuanling saves a gravely injured Xie Xuechen within the Dark Domain, she forces him to accompany her, leveraging a life debt. As they journey together, their initial distrust and hidden agendas give way to mutual respect and unspoken emotions. Amidst their evolving relationship, a dark conspiracy surrounding the legendary Chaos Pearl thrusts them into a series of life-and-death trials. In a moment of ultimate sacrifice, Mu Xuanling gives her life to save the world. Determined to defy fate, Xie Xuechen alters destiny itself, traveling back in time to rescue her. With the cycle of countless lifetimes finally broken, Xie Xuechen reclaims his true identity as Emperor Zhaoming. However, his original form has been transformed into a Fallen God. Mu Xuanling's enduring love redeems the Fallen God, averting the impending apocalypse and restoring peace to the realm.