When Duke Felmet secretly assassinates King Verence to become the new king, three good witches Nanny Ogg, Granny Weatherwax and Magrat Garlick serendipitously end up taking care of the real heir - Verence's baby boy.
The witches bless the baby and give it to a troupe of traveling actors to raise it. Duke Felmet becomes paranoid that a witch will bring about his downfall.
The land itself becomes displeased with Felmet's chaotic evil rule. Nanny Ogg gets arrested while looking for her cat. Magrat and Granny Weatherwax go each on her own to rescue Nanny Ogg.
After a chance meeting in Ankh-Morpork, the court's fool on Felmet's orders inadvertently hires Verence's son's troupe to write a play that tells Felmet's twisted version of events that made him king.
The witches go to the castle to see the play and, after realizing that it's nothing but Felmet's propaganda piece, they eventually decide to make its plot more truthful.
