Kanojo no Imouto to Himitsu no Stay Home ~Uchiki Musume ga Haitoku Netori!~

Sayoko Amafune and Aritomo Harase have started living together in preparation for their marriage. A little while later, Sayoko's parents' house undergoes renovations, and her parents decide to move into a rented house close to their place of work. However, Sayoko's younger sister Emiru has to live with Aritomo and Sayako for some time since Aritomo's place is near her school and her parent's place is too far away from her school. Emiru is not good at socializing and is a bit out of her element. At first, she doesn't greet Aritomo or even speak to him. However, over time, she opens up to Aritomo and she is no longer sullen. Then one day. While working side by side with Emiru, Emiru pretended to accidentally cling to Aritomo and then entwined her legs around him. She stares at Aritomo awkwardly but seductively......