His rule: No sexual relations until age 18! Her rule: No rules.Free-spirited Yuri Hasegawa and straitlaced Keiichiro Katsuragi have fallen in love. But his elite political family-producing a line of prime ministers-does not allow male descendants to engage in any sexual relations until they are 18. Can the physically affectionate Yuri and rule-abiding Keiichiro keep their relationship strictly chaste?It\'s almost Yuri\'s birthday, and Keiichiro\'s present for her is none other than a three-day trip to Kyoto! But as always, the couple isn\'t allowed any intimate contact... How will Keiichiro\'s birthday surprise for Yuri turn out?!