In the Nine Heavens Cultivation Realm, Ling Qingye, a cold and brilliant prodigy of an immortal sect, becomes the sole disciple of the Venerable Han Guang. What she doesn't know is that the bond between master and disciple began as part of a cycle of reincarnation spanning a thousand years. The Venerable Han Guang is cold and ruthless, cultivates the Heartless Dao, and wields the Severing Sword, which draws blood with every strike. Amid the charged intimacy of their daily training and the times he rescues her from danger, Ling Qingye gradually falls for him. She has no idea that she is merely the “wife” her master chose to prove his Heartless Dao.
When pressure from the sect mounts and a portrait from her past life comes to light, a misunderstanding over the words “she was only a tool for surviving the tribulation” shatters Ling Qingye's heart. She leaves the immortal sect in defiance and falls into the demonic path. On her quest for revenge, she cultivates the Heart of Love and Hatred, which turns love and hate into power, and leads the demonic forces into battle against her master. Yet, through their repeated struggles to the death and fragments of a diary found in a secret chamber, a greater truth gradually emerges: every time Han Guang “killed his wife,” he was actually protecting her soul from being destroyed in the Calamity of Annihilation and helping her reincarnate. Beneath his cold exterior lay a passion and sacrifice he had been unable to put into words for a thousand years.
From their falling-out as master and disciple to uncovering the secret of the Nine Heavens Prison, from tormenting one another to being forced to join forces against an ancient evil god, memories of their past lives awaken one by one through the Mirror of Reincarnation. In the end, fate demands that one of them sacrifice themselves to restart the world. Can they wield the ultimate mystery of the Heart of Love and Hatred, replacing hate with love, and together break this endless cycle of reincarnation to win a perfect ending for each other and the whole world?
