On a sweltering summer day, Yui's unemployed brother-in-law shows up at the apartment where Yui No lives with her husband's parents. Even though he's her husband's brother, Yui feels uneasy living with a stranger... and her premonition turns out to be correct! One tropical night, her brother-in-law peeks at the voluptuous sweat gushing from Yui No body and waits for the family to leave before attacking Yui...