One of the Discworld novels. The witches Granny Weatherwax, Nanny Ogg and Magrat Garlick travel to the distant city of Genua to make sure that a servant girl do... » 

One of the Discworld novels. The witches Granny Weatherwax, Nanny Ogg and Magrat Garlick travel to the distant city of Genua to make sure that a servant girl doesn't marry a prince. But all they've got is Mrs Gogol's voodoo, a one-eyed cat and a secondhand magic wand that can only do pumpkins. «