Katherine Arden’s The Girl in the Tower is the second novel in the Winternight Trilogy, picking up immediately after the events of The Bear and the Nightingale. The preceding book establishes the central conflict of the series: the clash between Slavic folklore and the encroaching influence of Orthodox Christianity in medieval Russia. It introduces the protagonist of the series, Vasilisa “Vasya” Petrovna, who possesses the rare ability to see and communicate with the chyerti, the animistic spirits of the household and wilderness. 

Vasya’s refusal to renounce these spirits and her reverence for the old ways put her in direct opposition to the charismatic priest Konstantin Nikonovich, whose fiery sermons turn her village of Lesnaya Zemlya against its traditional beliefs. As the villagers’ faith in the chyerti wanes, so does the spirits’ power, leaving the land vulnerable to Medved, the ancient bear-god of fear and chaos. Vasya is the sole opposition to Konstantin and Medved, supported by her uneasy alliance with Morozko, the winter king and death god, who is Medved’s brother.

In the novel’s climax, Vasya confronts Medved, who has been aided by her devout and terrified stepmother, Anna, and strengthened by Konstantin’s bitter hatred of Vasya and the old beliefs.