After transmigrating into a novel, the female lead discovers that her system's mission is to kill the ultimate villain. Mistaking her senior martial brother for an upright third male lead, she reveals the villain's secrets to secure his protection. Only after they marry does she discover that her husband is the very ancient monster who has lived for an unknown number of years. Her attempt to escape fails, and Liu Fusheng develops dementia in his old age. Every time he meets her, he falls in love at first sight and declares, “Bring her to me. I want her.” Later, he gives up eternal life and falls into a deep slumber, transforming into a little red sparrow. The system sends the female lead back to the modern world, but the male lead threatens to destroy the world of the novel, forcing her to return. After many twists and turns, the two start over from the beginning and spend every year together as a family of three.