Taiyo Asano has been on his own ever since his parents died and the only one who seems to care for him is his childhood friend and classmate, Mutsumi Yozakura. But Mutsumi has a secret-she is the head of a family of spies! And on top of that, her brother Kyoichiro is dangerously protective of her! To stop Kyoichiro from killing him, Taiyo and Mutsumi must take the ultimate leap-marriage! Because in the Yozakura family, family cannot kill family.

Mutsumi's been kidnapped by Hanawa, a spy who is a master florist! The entire family is dispatched to save her. Having failed to put up a fight against Hanawa the first time they met, will Taiyo be able to defeat him this time? Later, Taiyo is arrested by a mysterious detective who seems to know a lot more about the Yozakura family than he should...