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!

Kyoichiro vanishes, leaving behind only a note that says, "Don't look for me!" At first, everyone thinks it's just another one of his typical sulking fits, and they take advantage of his absence to cut loose. But it doesn't take long for them to realize he's actually pursuing Momo. The whole family goes after him, only to stumble across a shocking sight!