By chance, Wen Yifan and Sang Yan, a high school classmate she once disliked, began to live together. Because of the past youth, the relationship between the two was once stiff and awkward. Although they lived under the same roof, they were like two strangers with no blood relationship. As they got along better and Wen Yifan's sleepwalking appeared, the gap between them was broken, the misunderstanding was eliminated, and the regrets of youth were made up.