Plagued by haunting visions and voices, high school senior Olive Claire is still reeling from the loss of her guardian and grandmother, Alexandra, whose passing coincided with the perturbing accidental death of a classmate. Olive tries to return to make things return to normal at home in rural North Carolina, but an attack on her life by a man with wings like oil slicks brings to light a revelation: she is a magus, part of an international magical community ruled and policed by the Council. The fantastical news is undercut by her discovery of the violent, power-seeking Inanimalia, a race of chimera and shapeshifters with a mysterious interest in Olive. Furthermore, many of her powers and memories have been bound, hidden from her by her own late grandmother without explanation. Olive reluctantly absconds to the magi capital in Ireland to learn more about her culture and family history, which is riddled with bizarre, violent phenomena. The experience will challenge her expectations and muddle her beliefs as she learns more about both races and their pasts. Meanwhile, her friends from high school-Tally, Rose, and Marcus-begin investigating the demise of their classmate after stumbling upon a shocking piece of evidence: her severed head, hidden in the woods outside town. Unsure of who to trust, they try to unravel the cover-up, which grows stranger at every turn. Although separated, Olive's and her friends' quests will end up intertwining in startling ways and begin their perilous journey of navigating the centuries-old relationship between the magi and Inanimalia.