Melanie Smith has been mysteriously changed from angel to demon for unknown reasons. She doesn't know who, how, or why... only that she is not herself anymore. And that she still has some of her angelic abilities.

She eventually is found by a little boy and his butler, and taken in by them. She becomes a maid, and tries to hide her identity from the other workers and the master. The butler seems to have some suspicions, but she doesn't let him have them for too long.

One night, the master gets kidnapped, and the only way to help save him is to use her newly found demonic abilities, along with her angel ones. Will she use them and blow her cover? Or will she let the butler handle the dirty work?