Two years after the events of A Hat Full of Sky, Tiffany Aching, now 13 years old, is training with the witch Miss Treason. But when she takes Tiffany to witness the secret dark morris - the morris dance (performed wearing black clothes and octiron bells) that welcomes in the winter, Tiffany finds herself drawn into the dance and joins in. She finds herself face to face with the Wintersmith - winter himself - who mistakes her for the Summer Lady and falls in love with her.
Unknowingly, Tiffany drops her silver horse pendant (a gift from Roland, the Baron's son) during the Dance. The Wintersmith uses the pendant to find Tiffany and give her back the pendant during their second encounter. From then on, he uses the pendant to find her and deliver his gifts (delicate roses made of ice, her name written in frost on every window, Tiffany-shaped snowflakes, and icebergs in her shape). The elder witches, including Granny Weatherwax and Nanny Ogg, discover that the Wintersmith has been tracking her. Granny Weatherwax demands that she throw her silver horse pendant into Lancre Gorge.
Things get trickier for Tiffany when she discovers she has some of the Summer Lady's powers - plants start to grow where she walks barefooted, and the Cornucopia (Horn of Plenty) appears, causing problems by spurting out food and animals.
Before the problem with Tiffany and the Wintersmith is resolved, Miss Treason dies (she was 111, but claimed to be 113 because she felt that 111 sounded adolescent). The young witch Annagramma acquires Miss Treason's cottage, but she needs help from Tiffany and the other young witches before she can learn to cope on her own. Tiffany goes to live with Nanny Ogg.
The Wintersmith decides that the reason Tiffany will not be his is that he is not human. Learning a simple rhyme from some children about what basic elements comprise a human body, he sets off to gather the correct ingredients. He makes himself a body out of these elements and pursues Tiffany, but without truly understanding what it is to be human.
Granny Weatherwax instructs the Nac Mac Feegles, who watch Tiffany closely to protect their "big wee hag," to find a Hero, namely her childhood acquaintance and incipient love interest, Roland. Roland must descend into the underworld, guided by the Nac Mac Feegles, and awaken the real Lady Summer from her storybook slumber. But first the Feegles help Roland train to use a sword by providing him a moving target (themselves inside a suit of armor).
Meanwhile, the Wintersmith continues to cover the land with Tiffany-shaped snowflakes. The harsh, prolonged winter starts burying houses, blocking roads, and killing off the sheep of the Chalk. Hiding inside her father's house, Tiffany is surprised to find her silver pendant inside a fish that her brother, Wentworth, has caught. This allows the Wintersmith to discover where she is, and he takes her to his ice palace, where she ultimately manages to stop him, melting him with a kiss, and fulfilling the Dance of Seasons, in which Summer and Winter die and are reborn in turn.
- Terry Pratchett, Wintersmith, Doubleday (2006) ISBN 978-0385609845
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