Riri's daughter, Noa, was troubled by her boyfriend, Kotetsu. She was frustrated by his gentle but indecisive and weak-willed nature, finding him unmanly. One day, her frustration exploded. Noa, strong-willed, verbally abused Kotetsu, then left him and the house. Riri felt pity for the deeply dejected Kotetsu and tried to encourage him. At that moment, Kotetsu revealed that he had grown up without a mother and had never known a mother's love. Riri's feelings for Kotetsu became a mix of his gentle nature, her responsibility for her daughter's harsh words, and his lack of maternal affection, leading to an overwhelming maternal instinct towards him. Kotetsu began to depend on Riri, and Riri found joy in being depended upon. Eventually, these emotions led them to desire each other. Kotetsu then decided to break up with Noa. Riri's subsequent actions led to their distorted love transforming into intense sexual encounters.