Severely allergic to felines, Yuuto Amakawa spends his mornings nursing a drippy nose courtesy of his friend Rinkos cat. But on his sixteenth birthday, its not just Rinkos pet thats riling up his allergies (to say nothing of his hormones)! Appearing before him is Himari, a buxom, sword-wielding cat spirit in human guise, who has sworn to protect Yuuto, now the target of vengeful spirits! Its clear that Yuutos allergies are the least of his problems - hes gonna need Himaris help if he wants to live to see his seventeenth birthday!