They collude with their beautiful brother's wife who is short on money to make stained panties for sale at auction, but they had decided that it was for money, but they both began to get horny and end up having creampie sex.

Erika's husband has been laid off from the company and is worried about daily living expenses. Unable to see Erika, her brother-in-law Wataru suggests that she sells used underwear at an online auction. Although confused, Erika decides that she needs to wear stains and photo evidence in order to sell for a high price, she makes a difficult decision to spend money. Later, the two, who have completely lost their sales, far exceeding expectations, try to take on extreme play in order to increase their profits even more... Erika notices Wataru's crotch, which has bulged into her.