Here we are, back in the Discworld. The witches Granny Weatherwax, Nanny Ogg, and Magrat have returned from an eight month trip abroad, and Magrat is somewhat surprised to find that her wedding to the King of Lancre is proceeding apace. The surprise is due to the fact that he didn't bother to ask her - apparently, as king, he doesn't. Magrat is sensible enough to clamp down on her outrage - she does like him, after all - and prepare to learn the business of queening, which appears to be mostly tapestry and sitting around.
But it's circle time, with the boundaries between worlds growing thin, and the euphemistically-termed Lords and Ladies (because if you say what they really are, you'll get the wrong idea) are attempting to break through to Lancre. And because Lancre is where Shakespearian parodies go to die, much of the novel borrows from A Midsummer Night's Dream. Though Shakespeare could never have come up with the Stick and Bucket Dance.
This is a strong novel in the series, reiterating how perception can affect reality, and about finding the strength to do what is necessary.