Originally published in 2013, Shift is the second book in the Silo series of postapocalyptic science fiction novels by Hugh Howey. Shift enriches the story of Juliette (which began in the first book, WOOL), by looking back and telling the story of Donald Keene, the architect of the silos—subterranean cities that house the remainder of humanity. In telling Donald’s story, Shift reveals the truth about the men who created World Order Operation Fifty (or WOOL, in which the “L” represents the Roman numeral for 50) in an attempt to save humanity. In addition, Shift gives background detail on Silo 17, the location that Juliette discovers after leaving her own home in Silo 18, and makes several connections that deepen revelations Juliette made at the end of WOOL. Finally, Shift connects Juliette to Donald, setting up the premise for the next novel in the series, Dirt.

The Silo series of novels inspired a television series called Silo that airs on Apple TV. Created by Graham Yost, it stars Rebecca Ferguson and Tim Robbins.

This guide references the Kindle e-book edition of Shift.

Content Warning: Shift contains violence and mentions of death by suicide and attempted suicide.

Plot Summary

In the year 2110, Troy wakes to start his first shift in Silo 1.

Sixty-one years earlier, Donald Keene is a new congressperson who meets with Senator Paul Thurman, an old family friend. He asks Donald to finish a bio-architectural design he began in college that he wants to use as an underground bunker for workers of the Containment and Disposal Facility (CAD-FAC), a nuclear waste facility, in the improbable event of an accident. Donald will work on this project with his former girlfriend, Anna Thurman (Paul Thurman’s daughter), and his college friend, Congressperson Mick Webb.

While working on the project, Donald visits Senator Thurman at a hospital where he’s being treated with nanobots. The idea of microscopic robots inside his body frightens Donald despite Thurman’s insistence that they can enter only the bodies of those whose DNA they’re programmed to repair. However, Donald’s fear increases after reading a book Thurman gave him, The Order, which leads him to seek medical care in secret and begin taking psychotherapeutic drugs.

The National Convention of 2052 is held on the newly completed grounds of CAD-FAC. Donald is onsite waiting for his wife, Helen, to arrive. Unfortunately, when she finally arrives, she’s at the tent designated for Tennessee, while Donald is at the one for Georgia. He attempts to go retrieve her, but Anna stops him just seconds before planes begin dropping nuclear weapons on the area. Donald rushes into the underground bunker with Anna, Thurman, and Donald’s sister, Charlotte.

In the year 2110, Troy is struggling through his first shift as Silo 1 leader. Silo 1 is the only silo that doesn’t have a thriving society. Instead, it contains storage rooms filled with cryo-frozen people, and the men are awakened on a recurring cycle to work shifts that last six months at a time. Troy’s role as head of Silo 1 is complicated by his slowly returning memories. As more of his memories return, Troy is deemed emotionally “unstable” and is put into a permanent sleep, not to be awakened again until it’s safe to leave the silos.

In 2212, Troy—who now recalls that he’s Donald Keene—is awakened under orders from Thurman. Silo 18 is falling, and several other silos have gone rogue. Victor, one of the men behind the nuclear strikes, became obsessed with a report Donald wrote on the fall of Silo 12, and Anna—who has also been awakened—believes this is the key to saving Silo 18. Donald works with Anna to figure out the problem while also researching what happened to his wife, Helen. He’s sad to learn that Helen married Mick and had two children. However, Donald manages to figure out that Silo 18 is resisting because someone in the silo remembers a time before life in the silos. He helps identify the person and order her execution. At the same time, Donald pinpoints why some people are resistant to the medication that wipes their memories, blaming it on the psychotherapeutic medication he was taking in secret. When Silo 18 is saved, Anna is put back to sleep, but Donald attempts to die by walking outside to the silo where Helen lived her final days. Thurman finds him and takes him back inside, putting him to sleep again.

In 2312, Silo 17 falls when someone opens the airlocks. Panic ensues. The IT shadow—second in command—locks his 16-year-old son, Jimmy, in a hidden bunker beneath the server room to keep him safe. For several years, Jimmy hides in the server room’s bunker while listening to the fighting that continues outside. Over time, however, he needs more supplies and begins sneaking out to explore the silo. As time passes, Jimmy sees fewer and fewer signs of other survivors. In the silo’s lowest level, he finds a cat in the flooding mechanical rooms. Jimmy and the cat, which he calls Shadow, survive on food growing in the farms and on canned goods. At the 34-year mark, Jimmy is shocked when a woman from the outside—later revealed as Juliette Nichols—invades his silo.

Donald is awakened again in 2345, but this time, the workers believe he’s Thurman for reasons unknown to Donald (but later implied to be a scheme by Anna to save the people in Silo 1). Donald learns that a cleaner wandered away from Silo 18. He instructs no one to interfere with the cleaner, Juliette Nichols, assuming that she’s walking toward an empty silo. At the same time, Donald uses his position as “Thurman” to gain access to information he shouldn’t have. Over time, Donald begins to put things together: He realizes that Anna and Mick worked together to put Donald in Silo 1 with Anna, thus allowing Mick to be with Helen in Silo 2. Donald awakens Anna, forces her to confess, and then kills her via an overdose of sleeping pills. In the aftermath of Anna’s death, Donald finds evidence that Thurman, Erskine, and Victor never intended to awaken the people in Silo 1 as they were told. Instead, their plan was to allow only one silo to survive once the world became inhabitable. Donald decides to prevent this. He wakes Thurman, confirms his own theories, and then shoots Thurman before putting him back in his cryopod. Donald speaks to Juliette over the radio, warning her that the truth can be dangerous.