In the course of assembling her thesis, Minerva uncovers information that reveals that Tremblay's most famous novel, The Vanishing, was inspired by a true story: Decades earlier, during the Great Depression, Tremblay attended the same university where Minerva is now studying and became obsessed with her beautiful and otherworldly roommate, who then disappeared under mysterious circumstances. As Minerva descends ever deeper into Tremblay's manuscript, she begins to sense that the malign force that stalked Tremblay and the missing girl might still walk the halls of the campus. These disturbing events also echo the stories Nana Alba told about her girlhood in 1900s Mexico, where she had a terrifying encounter with a witch. Minerva suspects that the same shadow that darkened the lives of her great-grandmother and Beatrice Tremblay is now threatening her own in 1990s Massachusetts.