About one gloomy girl named Mei who injures the most popular male student named Yamato. Somehow, Yamato likes Mei and one day, Yamato saves Mei from a stalker by kissing her. From that kiss, their love story begins.
From midnight to 5 AM, people gather at a high-end apartment in Roppongi to engage in promiscuous sexual activity. Story depicts the process of the men and women who meet for the first time there to have loveless sex.
Miyazaki asks Noboru and Momose to pretend they are dating to stop bad rumor about him. Both begin to act like a couple in front of others and soon he begins to develop feelings for Momose, who is still in love with Miyazaki.
A store owner and a magazine editor were hired as a temporary employee by The Louvre for a Mona Lisa exhibition to be held in Japan. The two soon discover a hidden puzzle of the Mona Lisa that will change their lives.