Lyla, a genius contract mage, spent three years in her past life collecting ninety-nine sacred cores to help her contract beast, the holy whale Neil, take human form—only for him to pierce her heart with his own hands and cast her into the blood-tide trench at the very moment of his transformation. Reborn on the day of the contract ceremony, she resolutely abandons the holy whale and chooses a dying little spirit snake instead. After Neil successfully takes human form, he teams up with her sister Evelyn to humiliate her at every turn—but no one suspects that the little snake is actually Poseidon, the Sea Emperor. As betrayals and old wounds from her past life surface one after another, Neil falls to his knees in regret—too late. Only Poseidon stands by her, steadfast and unwavering. In this life, she will no longer burn herself out for the wrong person. At last, she learns to live for herself.