After the catastrophic Twelfth Expedition, described in Annihilation, the second book of the Southern Reach trilogy introduces John Rodriguez, the new head of the government agency responsible for monitoring Area X. His first day is devoted to dealing with the aftermath of the last expedition. Area X itself remains a mystery. But following instructions from a higher authority, known only as the Voice, the self-proclaimed Control must struggle to restore order to his domain.

Through a series of interrogations, hidden notes, and hours of deeply unsettling video footage, the secrets of Area X begin to unravel, and what they reveal forces Control to confront a disturbing truth about both himself and the agency he swore to serve.

Shattered and under pressure to understand everything, Rodriguez retreats into his past in a labyrinthine search for answers. But the more he uncovers, the more he risks, as the secrets of the Southern Reach are darker than anyone could have imagined.