Junkichi, a younger brother who lives with his older sister. When Junkichi came home from work, his sister's friend, Kayo, was drinking with her sister. Junkichi, who drinks with him, is revealed to be a virgin before 30 by his older sister. When Kayo finds out about this, she seduces Junkichi, but Junkichi, who is a virgin, is at the mercy of her older woman, Kayo...
