The overall theme of Wyrd Sisters concerns the effect words can have on reality. Olwyn Vitoller's acting company builds a theater they name ' The Dysk' (after the Globe Theatre), and the company's plays include lines that allude to or are outright borrowed from Shakespeare's works. The book also contains references and allusions to Shakespeare's other works, and to Shakespeare's own life.

Further references include Duke Felmet's desperate attempts to wash the blood from his hand. The plot of Wyrd Sisters is largely an homage to William Shakespeare's tragedy Macbeth the book's first line of dialogue is the first line of the play, in similar circumstances ('When shall we three meet again?', spoken by one of three witches on a stormy night). Luckily, the jester turns out to be his brother and he becomes king instead. The only problem is that Tomjon does not want to be king. Meanwhile, the duke has decided to get a play written and performed that is favourable to him so he sends the jester to Ankh-Morpork to recruit the same travelling (now stationary) company that Tomjon is in. However, the kingdom is angry and doesn't want to wait 15 years so the witches move the kingdom forward in time.

The witches hand the crown and the child to a troupe of traveling actors, acknowledging that destiny will eventually take its course and the baby - Tomjon - will grow up to defeat Duke Felmet. King Verence I of Lancre is murdered by his cousin, Duke Felmet, and the King's crown and a baby are given by an escaping servant to the three witches. Wyrd Sisters features three witches: Granny Weatherwax Nanny Ogg, matriarch 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, covens and bubbling cauldrons, much to the annoyance of Granny Weatherwax and Nanny Ogg. One of two books made into an animated film.

Terry pratchett book sisters