Won-hee overhears the conversation between her mother, Kang, and her aunt Okbun, and is surprised that Won-gyu is not her brother. After all, Won-hee compares the blood type of her family with the blood type of her family and finds out a new fact. . On the other hand, Mrs. Kang, worried about Won-gyu, a three-year-old student, asks her to study extracurricularly with the daughter of her deputy principal, Se-hee. I can't hide my embarrassment. . (source: SBS)