Twelve-year-old Lennie Mercado loves magic. She practices her invisibility powers all the time (she can now stay invisible for fifteen seconds!), and she dreams of the day that she can visit her grandfather, the Prime Wizard de Pomporromp, at his magical estate.

Now Lennie has her chance. Poppop has decided to retire, and his grandchildren are coming from all over to compete in Wizardmatch. The winner inherits his title, his castle, and every single one of his unlimited magical powers. The losers get nothing. Lennie is desperate to win, but when Poppop creates a new rule to quelch any sibling rivalry, her thoughts turn from winning Wizardmatch to sabotaging it...even if it means betraying her family.