The main character, Kaede Minami has a crush on Setsu Yuki. Unfortuneately, Kaede is shy around her male classmates, so it is very difficult for her to date. One day, she buys a brightly colored mug and when she gets home, she finds an engraved note on the bottom of the mug and while pouring hot cocoa into the mug, a muglox named Mirumo appears.
It turns out Mirumo is the prince of the muglox world. Horrifed at the aspect to marry Rirumu, his princess-bride-to-be, Mirumo has escaped to the human world. Hot on his heels, however, are the bounty-hunter Yatshichi, Rirumu and many other muglox as well.