Story so far

Wool began with Sheriff Holston choosing to leave the underground silo where thousands lived beneath a poisonous surface. His wife Allison had discovered deleted records and image-making software, concluded that the outside was habitable, and volunteered to clean the cameras through which the inhabitants saw it. Three years after her death, Holston followed. His helmet showed a green world, but removing it exposed the wasteland; he died beside Allison. Deputy Marnes recommended Juliette Nichols, a mechanic from the deepest levels, as his successor. Mayor Jahns recruited her despite IT chief Bernard Holland's opposition. Mechanical had become Juliette's family after her brother Nicholas's death and her mother's suicide estranged her from her father, Dr. Peter Nichols. Bernard also resented her theft of IT heat tape, which she considered inferior to Mechanical's supplies. Returning upstairs, Jahns and Marnes finally acknowledged their love, but Jahns died after drinking poisoned water from Marnes's canteen, realizing he had been the target. IT security chief Sims had refilled their water. Bernard became acting mayor; Marnes was subsequently found hanging, apparently blaming himself for Jahns's death. Juliette investigated Holston's records, remembering his help after the suspicious death of her lover George Wilkins. Scottie, Walker's former apprentice, recovered files and recognized image-making software in Allison's correspondence. His frightened request to leave IT was followed by his reported suicide. Bernard installed Peter Billings as Juliette's deputy, arrested her, and confiscated her computer. Scottie's last message helped Juliette and Walker understand that cleaning suits were deliberately made to fail. Lukas Kyle, an IT worker who watched stars on the cafeteria screen, had grown close to Juliette, but she discouraged his attachment and stopped Mechanical chief Knox from resisting her arrest. Walker enlisted Supply to substitute better materials for her suit. Juliette survived her cleaning, recognized the helmet's false landscape, and crossed the hill without cleaning the cameras. She reached silo seventeen; Bernard secretly reported the crisis to silo one, identifying their home as eighteen. In seventeen, Solo told Juliette how he had hidden beneath IT during an uprising thirty-four years earlier. Maps revealed roughly fifty interconnected silos. Missing supplies suggested other survivors, and a digging machine beneath the flooded lower levels offered a possible way to tunnel home. Meanwhile, Knox and Supply chief Jove McLain led an armed expedition against IT and were ambushed. Knox died, Peter was wounded, and Lukas shot McLain as she prepared a bomb, which exploded among the attackers. Marck and Shirly escaped, but Marck died defending Mechanical's barricade. Weeks of siege followed under Jenkins and Harper. Walker and Shirly repaired a captured radio and heard other silos. Bernard chose Lukas as his shadow, confining him beneath IT to study the Order's instructions for crises. Juliette reached eighteen by telephone, and her conversations with Lukas deepened their attachment, although he refused her demand that he kill Bernard. A distant official confirmed Lukas as Bernard's successor in Operation Fifty of the World Order and acknowledged that the silo builders had caused the catastrophe outside. Bernard described forty-seven surviving silos and the destruction of silo ten after forbidden knowledge spread. In seventeen, Juliette adapted a cleaning suit to reach the submerged sump pumps and connect them to IT's independent power. Her air failed during the dive, but she escaped after breathing trapped air beneath the stairs. She surfaced to find Solo unconscious beside the overturned compressor. After reviving him and learning that his name was Jimmy, she discovered children surviving on the farms: Rickson, Helena and her baby, two younger boys, and Elise. Rickson attacked her with Jimmy's stolen wrench, and she wounded his leg before recognizing his age. Their parents were dead; their fear of the compressor helped explain Jimmy's injuries. Juliette offered help. Walker finally reached her as Mechanical fell. She urged her friends to stop fighting and abandon their attack on IT's cooling vents, but contact failed. Lukas learned that George's proposals for lateral mining and deeper levels had marked him for elimination. Bernard admitted that threats were secretly killed, then used a concealed radio to turn Lukas's request to leave confinement into an alleged request to go outside. Juliette forced open seventeen's caged radio and contacted eighteen, only to hear Bernard threaten to send Lukas out in a fatal suit. With Jimmy's help, she repaired another suit and made a protective blanket from good heat tape, promising to return for him and the children. She crossed the surface and entered eighteen's airlock as its doors opened. Believing the suited man inside was Lukas, she covered them both, but he fought free when the cleansing flames began. Juliette survived beneath the blanket with extensive burns. The dead man was not Lukas: Peter had intervened, and Bernard had been sent out instead.

Peter and the others pulled Juliette from the hot airlock and cut away her melting suit. She drifted through days of pain and medication in the infirmary on level thirty-three, where Lukas stayed beside her. When her mind cleared, she learned that the location offered both good treatment and protection. Notes from down deep brought the news of Knox's and Marck's deaths. She read them repeatedly, trying to distinguish the dead from those still signing their names, and longed to see Shirly, but visitors from below were not allowed. Lukas explained how Peter had saved him. While escorting Lukas toward his cleaning, Peter had heard Juliette alive over the radio and listened when Lukas challenged Bernard's account, told him Bernard had killed a man, and said he had proof. Reports of Mechanical's surrender came over the radio, yet Bernard still ordered the prisoners' deaths. With IT security a hundred levels away and the only gun up top in his own possession, Peter chose to exercise his authority as sheriff rather than obey Bernard. Juliette thanked him repeatedly during his visits. Weeks later, still wearing bandages and loose clothes to spare her scarred skin, she was finally cleared to travel. Lukas and Peter delayed her departure with a private meeting. Their admission that they had withheld some notes made her fear more deaths, but the concealed messages were congratulations. Bernard had been running unopposed for mayor; after he was sent to cleaning, the election was called off. News of Juliette's return nevertheless brought more than half the silo out to vote, and they elected her. She initially laughed at the idea and asked how to refuse. Peter's suggestion that she could shake hands, sign papers, and reassure people did little to persuade her. Lukas made the deeper appeal: the silo had a power vacuum, its leaders were inexperienced, and Juliette knew from seventeen how close eighteen had come to catastrophe. They had a chance to hold their home together. She agreed to consider the office only on her own terms: no more lying. Juliette argued that the actual danger outside was frightening enough without invented threats. She understood that the silos had been kept separate and ignorant so that trouble in one would not spread to the others, but rejected the cause behind that system. Her opposition was directed at the informed authorities controlling it, rather than the ordinary inhabitants of other silos. She wanted eighteen's people to know what they faced and act with shared purpose. Whether she became mayor or returned to Mechanical, she would spread the truth. Peter secured her agreement to do nothing rash until they met again, but Lukas recognized how firmly she had decided. Left alone with her, he admitted that he had also delayed because he did not want her to go. His trembling, which she first mistook for distress, became understandable when he kissed her. She kissed him back, and their affection finally became explicit. Lukas saw her to the landing, having padded her bag's strap to protect her wounds, and reminded her that she could radio him. Juliette expected to see him again in about a week. Instead of descending immediately toward Mechanical and her friends, she started upstairs: she would visit her father first. Meanwhile, in seventeen, Elise counted thirty-two steps down toward the water and returned to Jimmy with proof that its level was falling. She hugged him, delighted. Jimmy looked past the old bloodstain on the landing toward the receding flood and reached for his radio to tell Juliette.

Juliette is back in eighteen, scarred but able to travel, climbing toward her father before visiting her friends down deep. She is the people's choice for mayor, but taking office remains tied to her demand for truth; Peter and Lukas have yet to settle that course with her. Peter holds the sheriff's authority, Lukas has survived Bernard and openly returned Juliette's affection, and Bernard is dead. Knox, Marck, Jahns, Marnes, and the others lost cannot be restored by the fighting's end. In seventeen, Jimmy has the children for company, the pumps are lowering the water, and Juliette's promise to return remains alive, although no tunnel connects their homes. Beyond eighteen, the authorities behind the Order still exist. Juliette wants her silo to face them with knowledge, while its other leaders still fear what telling everyone the truth will mean.