Clover (Clamp) summary:

Kazuhiko is a black ops agent who is called on an unusual mission: he must escort Sue, an innocent waif who has lived in isolation for years, to an unknown destination. But there’s a dark reason for Sue’s life of captivity, and Kazuhiko discovers that his mission is more dangerous than it looks. From Tokyopop: Clover follows Sue and Kazuhiko to the isolated setting of Fairy Park. It is a journey into a futuristic world in which the government (Parliament) seeks to control Clovers--special children with amazing powers. As Sue learns more about herself, she comes to find that she is unique even among Clovers and with Kazuhiko's help strives to find out what Parliament's intentions for her are.