When Molly shows up on Castle Hangnail's doorstep to fill the vacancy for a wicked witch, the castle's minions are understandably dubious. After all, she is 12 years old, barely five feet tall, and quite polite. (The minions are used to tall, demanding evil sorceresses with razor-sharp cheekbones.) But the castle desperately needs a master or else the Board of Magic will decommission it, leaving all the minions without the home they love. So when Molly assures them that she is quite wicked indeed (so wicked! Really wicked!) and begins completing the tasks required by the Board of Magic for approval, everyone feels hopeful. Unfortunately it turns out that Molly has quite a few secrets, including the biggest one of all: that she isn't who she says she is.