Essentially a parody or calque of Macbeth, Wyrd Sisters features three witches: Granny Weatherwax; Nanny Ogg, monarch of a large tribe of Oggs, who owns the most evil cat in the world, (Greebo); and Magrat Garlick, the junior witch, who firmly believes in occult jewellery, even though none of it works.  King Verence I of Lancre is murdered by his cousin, Duke Felmet, and the King's son is given by an escaping servant to the three witches. The witches hand the child to a troupe of traveling actors, acknowledging that destiny will eventually take its course and Tomjon will grow up to defeat Duke Felmet.

Not so much a Discworld story as a homage to MacBeth set on the Discworld, but that doesn't matter too much to me. The three witches are quite possibly my favourite characters of the series, Granny, Nanny and Magrat work very well together in their own opinionated, headstrong ways. TP out dimensionalises WS by setting a play within a play within a play, allowing for extra free jokes. There's a cameo by the Librarian and Death pops by to forget a few lines. The ending is a happy one too, as Tomjon manages to avoid his destiny and do what he wants to do instead, leaving the throne clear for his older brother, the illegitimate son of the late king who was raised a fool and you'd have to be a fool to want to be a king anyway, so he fits the bill perfectly. Magrat as a goth takes me back to my troubled teens, although I suspect she doesn't have such easy access to black hair dye.