Tells the story of protagonist Masato Asakawa, a second-year high school student. Following his parents' sudden transfer to positions abroad, Masato ends up living alone with his childhood friend Chinogi Senou in the Asakawa family 3LDK apartment. With the university entrance exams coming up next year and without the supervision of his parents, Masato is expecting a careless life. However his parents have installed Chinogi's elder sister, a straight-laced miko as caretaker in their place. To make the entire setting more chaotic, the popular idol Ayase Miyashita, who is constantly pursued by the media, moves into the apartment after asking Masato a place to stay. Joining this interesting bunch of residents is the misterious runaway girl Noemi Yukimura. Sharing three rooms with three girls, Masato's situation now indeed can be referred to as curious.