Mana, the spirit of green living things, can be used for both good and evil, and an investigative office exists to keep the destructive power of Mana in check. Ruwen is a Mana Investigator who's been sent to a small town to check out a possible abuse of Mana situation. Once there, he meets the cheerful little girl Miniru, who eagerly guides him around the town. Could Miniru, who is suffering from a strange illness, have something to do with the Mana situation? (taken from MH)

The story is about a second-year high-school student named Junpei Kousaka, who not only hates cats but also is allergic to them. Unforunately, he happens to have a crush on a girl, Kaede Mizuno, who really loves cats. On the way home from school one day, Junpei kicks an empty can and happens to accidentally hit the Guardian Deity of Cats. Now he's able to understand cats but was practically given a curse. He has to grant 100 wishes from any cat or he'll turn into a cat himself.