In 1925, a young academic visits the Guthrie Asylum in Oklahoma to explore the native tribal belief in the snake god, Yig. There she is confronted by a bizarre creature, the sole living survivor of the nightmarish Halloween of 1889. As she learns the tragic tale of Walker and Audrey Davis- early residents of the Oklahoma Territory- she too begins to fall under the spell of an unrelenting fear that time cannot diminish.