Arikawa Manami (24) is a no-good girl who has no boyfriend, no regular employment and no savings. One day, her older sister, who she was living with, suddenly moved out and she had to hurriedly find a roommate so she can afford to pay the rent.

"Will you be okay with having a guy for a roommate?"

She thought it'd be too much if it was an unknown man but the person she was introduced to was her childhood friend, Atsuto. In the past, Manami used to call him Atsuko the okama because he was like a girl in many ways but he's now a very handsome guy!

Just when she thought that this would be the start of a romance, Atsuto said, "You better not fall in love with me"!? And thus begins their life as roommates where the rule is if you fall in love, you lose!