Shinji is dumped by his first girlfriend because he can't take her bra off, and because of that, he starts to distrust women. One day, Shinji saw her sex strategy book and secretly practiced in the bra of Nanami, his brother's wife who lives with her. Little by little, she regains her confidence, and Shinji, who becomes curious about Nanami doing housework with her big breasts shaking, instinctively hugs her, fondles her breasts, and tries to remove her bra... but fails! Lack of practice! ! and