This anime is based on a (non-adult) PS2 dating game, "Kimi Kiss". The goal of the game is that the protagonist (the player) becomes friends with a girl in a month. Different from the game, the anime is drawn from the perspective of three characters, Sanada Koichi, Aihara Kazuki, and Mizusawa Mao.

During spring break, while Koichi makes himself comfortable at home, a beautiful girl suddenly comes in. She acts as if it were her house and even begins to take a shower. To his surprise, she was Mao, his childhood friend. She came back to Japan after 2 years absence from France. Since Mao in his memory was an unsophisticated girl always wearing tick glasses, he is surprised that she has become so beautiful.