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? 
Yuri has become a maid at the Katsuragi family's second residence, where Keiichiro lives. An idyllic summer vacation full of love awaits the two...but it's never that simple in the Katsuragi household!