The AV industry, where the unscientific notion that 'small breasts = sensitivity' has become common knowledge, sets out to verify whether women with small breasts are truly sensitive. They approach women with A-cup breasts on the street with an invitation: 'Would you like to be a monitor for a breast enlargement massager?' Boarding the Mirror号, they undergo an oil massage on their nipples, and as they become more sensitive, their sexual desire gradually increases, leading to a naughty mood.