"Just for today, I don't want you to think of anyone but me." In the one city in Japan where polygamous marriage (AKA: Harem Marriage) is legal, Koharu has long since overcome her initial reluctance and is now happily married to Ryunosuke, Yuzu, and Madoka Date. Now, as the ice around her heart begins to melt and she accepts her love for Ryu, she embarks on a new mission: to overcome her coitophobia, starting with a romantic (and sexy) birthday date!