Iori, the eldest son of four brothers of the Kobayashi family, decides to move to Tokyo to attend college. While he looks for an apartment, he finds an ad that says "live-in house keeper in exchange for free rent." This poses a perfect opportunity for him. Growing up with three other kids in the family, he's used to taking care of other people, he can cook well, he is good at cleaning, and he can save money on rent. In this situation, Todo is his boss, landlord, roommate - and lover, too?