Komaki Kouichi, a high school student who loves to cook, is harshly rejected by his childhood friend for being “Girly” When a heartbroken Koichi returns to the apartment where he lives alone, he finds Hashiro Shiho, a high school girl who is a very popular idol, sitting uneasily on the sofa. Shiho has become his younger sister as a result of their parents’ remarriage, and Koichi cooks for her. But as a result, Shiho says she wants to quit her idol career and marry Koichi. ……! It’s a romantic comedy about two people living together, him with his idol stepsister, cooking together, going on a secret date in the city, taking a bath and bed together (!?!), and so on.