On an incandescent Midsummer Night in the Kingdom of Lancre, the Discworld celebrates the wedding of King Verence and his favorite witch, Magrat Garlick. But music and romance aren’t the only things filling the air. Magic and mischief are afoot, threatening to spoil the festivities.

On this special night, dreams are especially powerful—strong enough to break down the walls between realities. And some things you really don’t want coming through and crashing a good party. Like elves. Most of the denizens in the Discworld have forgotten what life was like with the elves around. But Granny Weatherwax, Nanny Ogg, and Magrat Garlick remember.

Even in a world of wizards, trolls, dwarves—and the odd orangutan—these pernicious fairies are particularly nasty. The witches know that if the elves aren’t driven back to the other side, it won’t only be champagne flowing through the streets.