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 and Keiichiro have gotten to know each other on their daily commute to their respective high schools.

Yuri makes a passionate love confession to Keiichiro, and he feels the same! Yuri rushes in to kiss her new boyfriend, but…!