The Society for the Protection of Mythical Creatures faces an existential threat as the shapeshifter Kullervo prepares to weaponize ancient beasts against humanity. Connie, a member of the society, must navigate the tension between the human world and the hidden realm of mythical creatures, which is currently suffering from environmental degradation. She is opposed by the malevolent Kullervo, who seeks to harness her unique abilities to initiate a global conflict. The narrative follows Connie and her friend Col as they attempt to thwart this impending war during a volatile summer season.

Readers frequently highlight the book's accessible prose and its focus on environmental stewardship as a central thematic pillar. Discussion often centers on the effectiveness of the world-building, particularly how the author integrates mythical creatures into a modern, polluted landscape. Critics note that the pacing remains consistent, moving steadily toward the final confrontation between Connie and Kullervo. The balance between character development and the external threat of war provides a clear structure that appeals to fans of creature-focused fantasy. Many readers appreciate the straightforward nature of the conflict and the clear stakes established early in the narrative.