There's a new witch in the broken castle of the Wicked Witch of the West. She calls herself The Sorceress Lady Mumps, and she wants to make Oz marvelous again. All she needs is three clever cronies and a powerful weapon. Meanwhile, at Reed Elementary, Mildred finds an old magnet stuck to the buckle of her old boot. Louise recognizes it immediately. But this charm has more magic than anyone ever knew. When Mildred and Louise and their friend Thaddeus and their enemy Sam find themselves at odds with Mumps in Oz, they realize just how powerful the magnet is.
