My name is Yoshino. I live with my father's new family of three, my stepmother. Lately, she seems worried about her figure, and when a friend of my mother's came to visit, she received a sample of "corrective underwear" as a gift and has started wearing it every day. While saying, "Yoshino-kun, how do you like this underwear?" she shows off her figure, but frankly, I feel completely lost...