Saul dreams of burning lighthouses on a monster’s head and wakes with fever, head pressure, and verse spilling into his thoughts. Charlie is away for another week on a night-fishing job. Hearing whispering in the lighthouse, Saul takes an ax and climbs the dark stairs, noticing the lens has gone silent—the light is out.

In the lantern room, he finds Suzanne, Henry, and an unfamiliar woman in an overcoat and red scarf near the extinguished lens. He turns on the lights and confronts them with the raised ax. Henry tells him to go back to sleep. Saul accuses them of trespassing and turning off the light. Henry approaches and urgently whispers for him to leave. Suzanne speaks in a hypnotic tone, commanding Saul to put down the ax and sleep. Resisting, Saul swings the ax into the floorboards and orders them out. Henry agrees to leave; the woman gives Saul a mysterious smile as they descend. After switching the lens back on, Saul finds no sign of them outside—only a faint motorboat running without lights and a pulsing red dot from the island.

Henry reappears alone at the door. He confesses that he made the hole in the lens because he believed there was “something” inside. He did so without Suzanne’s knowledge because Suzanne does not share his conviction that some spiritual presence haunts the lighthouse. He accuses Saul of knowing the truth about the lighthouse and keeping it secret. When Saul asks about the strange woman, Henry tells him to forget he saw her, then walks away into the night.

Control lies amid debris from the wall the biologist-creature destroyed, playing dead as the creature probes the room. The creature forces him to see Lowry’s manipulations and his mother’s complicity, along with hazy childhood memories, then rejects and withdraws from him. Control weeps on the floor, feeling that control is meaningless.

Later, Grace finds him and returns his father’s carving. On the landing, Control is overwhelmed by their distance from Earth and wonders if Central monitored his childhood memories. He recalls two lost days at Central before his assignment, which his mother dismissed as paranoia. Grace bandages his injuries and confirms that he can still move. When Control asks what the biologist shared with Ghost Bird and what side she is on, Ghost Bird reveals that the biologist destroyed the convoy. Grace confirms this and explains that she has learned to avoid the creature. Control suggests they give in and wait as the biologist did; Ghost Bird replies that the biologist earned the right to choose her fate.

Ghost Bird suggests that they need another way out besides the hole in the sea. Tearing pages from Whitby’s document, Control proposes that they go back into the tower and neutralize the Crawler. Ghost Bird calls it a “suicide mission,” but Control clings to the hope that the director believed the Crawler could be changed. Grace says they have one advantage no one else had: Ghost Bird, the sole copy of the director’s last plan.

The Director receives a framed photograph from Lowry, showing the Director as a child with the lighthouse keeper and his assistant. His note makes clear that he intends to extort the Director, since the photograph is evidence that she grew up inside what is now Area X. She orders Grace to pull all files on Jackie Severance and her son, John Rodriguez (identified as “Control” in the Ghost Bird chapters), to find their connection to Lowry.

She reflects on returning from Area X with an indestructible plant and a nonfunctional cell phone. The plant is found to be unkillable; samples go to Central and Lowry. At a status meeting, Whitby suggests it is not actually a plant. He later shares theories about quantum mechanics and inter-organism communication. The old phone cannot be made to work, and Lowry insists she keep it.

Lowry announces another eleventh expedition—that is, another expedition in what will come to be called the eleventh cycle of expeditions—with a device implanted in the psychologist’s brain to enhance his memory and enable Lowry to surveil the team. Twelve months later, the expedition returns, but they are no longer themselves, and their memories are hazy; 18 months later, all are dead of cancer. Morale worsens. Jackie Severance begins visiting regularly as Central’s emissary, questioning the Director.

The Director paints the words from the topographical anomaly on a hidden wall in her office and draws a map of Area X, including the Southern Reach itself. Grace finds her painting and expresses concern. The Director tells Grace she is ordering the last eleventh expedition’s bodies exhumed, and Grace offers to help paint the map. On the rooftop, Grace asks if this is all part of a plan, and the Director lies that it is. She dreams of a centuries-long war between Central and Area X.

While walking on the beach, Saul experiences a vision of a burning object falling from the sky, creating a massive wave that destroys him. At the vision’s center, he sees the eight-leaved pattern of the strange plant that pricked his thumb. The vision ends, leaving the world restored but Saul deeply shaken.

He sits by a tidal pool on the rocks, trying to recover. Gloria finds him there. After sitting together in silence, they have a lighthearted conversation, and Gloria tells Saul what the lighthouse teaches her: to work hard, keep clean, be honest, and be nice to people. They begin using first names with each other for the first time.

Gloria says she is leaving to stay with her father for two months because her mother lost her second job. As her mother arrives to pick her up, Saul helps Gloria to her feet. She says goodbye and asks him to save the tidal pool for her. As she runs off, Saul impulsively shouts for her not to forget him and to take care of herself. She waves and says something he cannot hear before disappearing. In the tidal pool below, Saul observes a fish with a small red crab in its mouth.

Ghost Bird, Control, and Grace reach the mainland by boat in late afternoon. They observe the lighthouse, scorched by fire, with its lens extinguished. Grace explains that the border commander burned it along with the journals inside, though Ghost Bird senses that Grace is still withholding details. Grace tosses the biologist’s island account and journal through the open door, and they move on without entering.

As they travel inland, Control and Grace discuss what they miss. Grace mentions standing on the Southern Reach rooftop with the Director, making plans. Ghost Bird feels increasingly separate from them and contemplates her allegiance to the Director and the lighthouse keeper. She muses that the biologist’s transformation was the only correct response and that language is ultimately futile.

They discuss Grace’s theory that walking across the border leads somewhere different than going through the door. Ghost Bird recalls the devastation she saw in the corridor into Area X and wonders if it was real. As they travel through the marsh, they smell burning, and Ghost Bird sees something moving through the sky that the others cannot perceive.

One spring day, about four months after the last eleventh expedition member died, the Director sees Whitby by the swamp lake, washing a small brown mouse with intense care. She reflects on his apparent recovery over recent months.

She asks about the mouse, and he says he found it in the attic at home. Whitby then reveals that the immortal plant bloomed the previous night in the storage cathedral—a translucent white flower that disintegrated within an hour. He took no photos because he thought it would last longer.

The Director instructs him to write a report for her eyes only and tells him he cannot bring the mouse into the building again. She visits the storage cathedral in a purification suit and examines the plant, finding no evidence of a flower—only residue that later tests as pine resin from a previous sample. She wonders if the bloom existed only in Whitby’s mind and decides to put the plant under constant surveillance. She recognizes she is chained to Whitby just as Lowry is tethered to her.

A week later, at a bar, she reflects on Whitby’s choice not to name the mouse, comparing it to Southern Reach expedition protocol of referring to expedition members by their roles rather than their names, which leads her to consider the files for a 12th expedition, with the biologist’s file on top.

Saul’s journal mentions wildlife sightings and more sermon fragments. Feeling better after his illness, he goes to the village bar, where Charlie has saved them a table before his night-fishing trip. Charlie mentions catching strange sea creatures he threw back, then tells Saul that a friend saw the Science and Séance Brigade on Failure Island loading boxes into motorboats heading west along the coast.

Saul feels watched and spots Henry standing across the room by the door. As Saul stares, the room darkens, light gathers around Henry, and the band’s music distorts. Saul feels vertigo and a return of the symptoms he felt shortly after being pricked by the strange plant. He forces himself to look away, and the room returns to normal. When he looks back, Henry is gone.

Worried by Saul’s odd behavior, Charlie asks if he is okay. Struck by a premonition, Saul urges Charlie to leave for his trip. He holds Charlie for an extra moment, trying to preserve the feeling, before Charlie departs into the night.

In a feverish state the night before reaching the topographical anomaly, Control thinks about the biologist unlocking something inside him and the light at the tower’s bottom. Lying on pine moss with Ghost Bird holding him, he tells Grace it would not have mattered if she had told him everything at the Southern Reach. He recalls his father’s advice about passion and knowing when to move on.

In the morning, they see smoke and fire on the horizon and hear sounds like gunfire. In a reflection on the water, Control sees a distorted vision of soldiers attacking one another. Grace and Ghost Bird debate who should descend into the tower; Ghost Bird insists she should go alone.

At the entrance to the topographical anomaly, Control takes command. He orders Grace to stand guard at the top with the rifles and tells Ghost Bird she will accompany him but that he will lead the way. He sets a three-hour limit; if they are not back by then, Grace is released from responsibility. Grace agrees and warns them to hold on to whatever is in their heads now, because going down may leave nothing of it.

Control wonders what is coiled in his head and how it will affect the outcome, noting that his true goal is not to reach the Crawler but to understand the brightness that came with him. Control and Ghost Bird descend into the tower.