Hitozuma♪ Kasumi-san ~Oyako to Kyoudou Seikatsu~

Ryouji Matsubara, a college student attending a university in a certain regional city, currently lives alone in an apartment.
His uncle—his father’s younger brother—and his family live nearby, and toward the end of the month when money gets tight, he often goes over for meals or helps his cousin Mio with her studies, maintaining a relatively close relationship with his relatives.
Since his uncle was constantly busy traveling all over the country, Ryouji had become a reliable presence for his cousin Mio and his uncle’s wife, Kasumi. One day, Ryouji received a call from Kasumi on his cell phone. Her voice was trembling on the other end of the line, and when he asked what had happened, it turned out their home had apparently been burglarized.
After that incident, Ryouji’s uncle, Toshishi, suggested that he move out of his apartment and come live with them.
Ryouji hesitated at first, but after strong encouragement from Kasumi and Mio, he decided to move in with his uncle’s family.
Ryouji, who harbored a faint crush on Kasumi, found himself unconsciously letting his imagination run wild.

[Translated from the official site]