He is a 13yearold high school student in Japan. He is curious, introspective, and shy. Jin Mo develops a strange and intriguing infatuation with his 31yearold neighbor, Cai Yaru, after noticing her during a package delivery. He struggles with the intensity of his feelings and finds it difficult to process normal relationships due to his past experiences. Despite his age, he displays remarkable maturity in handling complex emotions and situations.
She is a 31yearold high school Japanese studies teacher in Japan. She is elegant, gentle, and oblivious. Cai lives alone and stands out to Jin Mo through a chance encounter when he sees her in her pajamas accepting a package. Her demeanor and appearance greatly impact Jin Mo, leading to an unusual fixation. Despite her kind nature and professionalism in her field, she is unaware of the impression she makes on the young boy and the potential consequences.