Curston is experiencing an unusually cold winter, with lots of snow. Unfortunately, the weather means that the town is running short of everything, food, cold-weather gear and other things the town needs to survive. Moyra's mother, with her father in Prison again, has taken to knitting scarves from probably the ugliest colors of wool Moyra has ever seen, and selling them in the marketplace.
Even if the colors are ugly, the lack of cold-weather garb to deal with the freezing temperatures means that they are still selling. When Zellach and Driskoll come by offering to buy Moyra some hot chocolate and engage in a snowball fight, she gladly agrees. Moyra is a little touchy because of her family's lack of money, but she is able to forget her troubles as she and the boys enjoy a raging snow fight in the Cathedral square. During the fight, Zellach uses his magic to make a huge snowball to chase Moyra, who dodges behind one of the Cathedral's pillars to hide. After it hits, she sees two snowballs. When she picks up the second, it feels curiously heavy. Thinking it a rock, she knocks the snow off it and finds a huge blue diamond.
Moyra happily thinks of selling it to provide for her mother and her, but hides it in her pouch when Zellach and Driskoll's father comes calling. It seems the supply wagons the town was expecting are very late, and the three go looking for them, wanting to be back before dark because winter wolves have been sighted outside the town after sunset. The find a wagon, but it's looted and empty. They also find a huge palace of ice and a room filled with snow globes containing tiny people that look almost real. They almost linger there too long and barely make it back into town before they become a wolf meal.
Moyra returns home, but isn't able to share news of the diamond with her mother, either. That night, she has horrible dreams about the diamond. She resolves to ask Kendric, Zellach's mentor and a powerful mage, about the diamond, but he cannot be found. The only clue they have to his whereabouts is the book he gave Zellach before he disappeared.
Meanwhile, another man, Fridjolf, comes to town, bearing supplies, which he sells at minimal cost, including a huge load of wool yarn that Moyra's mother eagerly buys to knit into more scarves. The man gives the children of the town toys and Gingerbread, and Moyra thinks about selling the diamond to the merchant, knowing her family desperately needs the money. However, something about Fridjoldf disturbs her and she holds back at the last minute. She also points out that the half-orc driving Fridjolf's wagon looks exactly like one she saw in one of the snow-globes at the ice palace.
She, Driskoll and Zellach attempt to decipher the book that Kendick gave Zellach, but Zellach's grasp of Elvish isn't the best, and he can only tell it has something to do with amulets of fire to banish the cold. Moyra finds the first one, along with another clue, which they sit down to translate.
Fridjolf continues to turn up around Moyra and her mother, gifting them both with expensive clothing, but worries Moyra when he asks if she has any gems she wishes to sell... like huge blue diamonds, perchance? He promises her he will give her a great deal of money for it, but Moyra tells him she has no such stone. Moyra knows something is definitely strange about the man, so she hides the stone after she is nearly pickpocketed on the street.
More winter weather continues to bombard the town, and the three Knights find that animals only known in the lands to the far north seem to have invaded Curston, such as ice wyrms. The three use their fire amulets to fight off the creatures, and Moyra is annoyed when no one but her seems to find Fridjolf frightening. But it takes a party at Fridjolf's ice manor to expose Fridjolf for what he is and what he truly wants... and it's not good for Curston.
I really like this series of books, even if they are targeted for younger readers, as they have superior characterization and allow the children to be the real heroes, while not giving them any kind of super intelligence or other ability, save for Kellach's magic.
This book focusses on Moyra, the thief of the party. We get to see how Moyra is driven by concern for her family and their lack of wealth, which is mainly due to her father's complete ineptitude as a thief and constantly landing in jail for various crimes. Sometimes, she resents her friends Zellach and Driskoll a bit for their relative wealth compared to her, but they and she are friends, and she knows they like her no matter how poor or wealthy she is. This book brings out a lot about Moyra's character, and is a fascinating look at her. Very highly recommended.