Two years from 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 - the winter himself - who mistakes her for the Lady Summer 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. And from there on in, he uses the pendant to find her and deliver his gifts (delicate ice roses, her name written in frost on every window, Tiffany-shaped snowflakes, and in distant seas icebergs in her shape). The elder witches, including Granny Weatherwax and Nanny Ogg try to hide her, realize how the Wintersmith has been tracking her, and demand for her to throw her silver horse pendant into Lancre Gorge.  But things get trickier for Tiffany. She has some of the Lady Summer's powers - plants start to grow where she walks barefooted. 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 it sounded better). Annagramma acquires the cottage (needing help for the first few days from Tiffany and the other young witches) and Tiffany goes to live with Nanny Ogg.  The Wintersmith realizes that Tiffany will not be his because he is not human. Learning a simple rhyme from children, he teaches himself the basic elements that makes up the human body. He makes himself a body out of these elements and pursues her, not truly understanding still what it is to be human.  Granny Weatherwax urges the Nac Mac Feegles, who watch Tiffany closely to protect their "wee big hag," to find a Hero. They find Roland. He is needed reawaken the real Summer Lady from the Underworld. After a few days of helping Roland sword-train with a moving target (themselves inside a suit of armour), they attempt to take Roland to the Underworld. They succeed after a certain degree of bickering with the ferryman.  Meanwhile, the Wintersmith has covered the land with Tiffany-snowflakes. Snowflakes were the only gifts Tiffany didn't refuse to receive from him. The harsh prolonged winter starts blocking houses and roads and killing off the sheep of the Chalk. Hiding inside her father's house, Tiffany finds her pendant inside a fish her brother, Wentworth, caught. She put the pendant back on when the service of a witch is needed by her father and the people of the Chalk. The snow is getting worse and Wentworth goes missing again. Using a skill she learned from Granny Weatherwax, Tiffany melts some of the snow to save a few sheep and find her brother. The Wintersmith finds Tiffany and takes her to his ice palace, where she ultimately manages to stop him with the same skill she used to find her brother, melting him with a kiss with the heat of the sun behind it, and fulfilling the Dance of Seasons, where Summer and Winter die and are reborn in turn.

At 9, Tiffany Aching defeated the cruel Queen of Fairyland. At 11, she battled an ancient body-stealing evil. At 13, Tiffany faces a new challenge: a boy. And boys can be a bit of a problem when you're thirteen. . . . But the Wintersmith isn't "exactly" a boy. He is Winter itself-snow, gales, icicles-all of it. When he has a crush on Tiffany, he may make her roses out of ice, but his nature is blizzards and avalanches. And he wants Tiffany to stay in his gleaming, frozen world. Forever. Tiffany will need all her cunning to make it to Spring. She'll also need her friends, from junior witches to the legendary Granny Weatherwax. They- "Crivens!" Tiffany will need the Wee Free Men too! She'll have the help of the bravest, toughest, smelliest pictsies ever to be banished from Fairyland-whether she wants it or not. It's going to be a cold, cold season, because if Tiffany doesn't survive until Spring - Spring won't come.