When I woke up, my wife's sister was sleeping next to me...

The bedroom was shining in by the sun...I woke up with a hangover one day, and one day I noticed a woman's hands were touching her body. I thought it was my wife, so I flipped through my futon as if to trace my hand, and an incredible sight came flying in. Yui, my wife's younger sister, who has come to our house to look for a job since yesterday, has been sleeping naked! "It's bad... This situation is too bad..." She somehow managed to survive without her wife finding out, but ever since then... Yui-chan has been seducing her to play with me, stealing her eyes...