Romance! A crazy, overprotective brother! And.spies?! 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. Preparation for Mission: Yozakura Frontlines to capture Kawashita is underway, and the family gets help from its allies--and even some old enemies.While the rest of the family is at work, Taiyo receives special training from Grandpa Ban to unlock the Yozakura family's secret power--Blooming. Every family member, including those married into the family, have their own Blooming, and Taiyo must unlock his before the mission begins. Time is of the essence, and as the decisive battle waits on the horizon, Kyoichiro tasks Taiyo with a heartfelt secondary mission he has to keep secret, even from the other siblings.