Niina Keito is always surrounded by girls who're into casual relationships because of his showy looks and "playboy" demeanour, but he's actually a pure-hearted shoujo fan who's never even had sex before! On the other hand, there's Takizawa Ryou: the picture of a studious, courteous prince in front of the girls but secretly a mean-spirited guy who doesn't care for them one bit. These two polar opposites are newly stepbrothers and therefore forced to live under one roof, but this, as well as the fact that their true personalities are completely different from their chosen images, are the two secrets they've both agreed to keep for each other. But one day, quite out of the blue, Takizawa kisses Niina and says, "Choose me. I'll love you for who you are"!?