Warning: this article contains spoilers
After almost three seasons of questions about why humanity retreated underground, Silo takes a major step towards explaining what drove them there.
Episode eight reveals not only why the silos were built, but also the catastrophe their creators believed would bring about the end of civilisation. And with only two episodes remaining, the two timelines are now more closely connected than ever.
The episode opens with Lucas Kyle (Avi Nash) and Patrick Kennedy (Rick Gomez), who survived their journey from Silo 18 despite The Algorithm previously declaring them “neutralised”. The pair reaches Silo 17, allowing Juliette Nichols (Rebecca Ferguson) to make contact with Jimmy (Steve Zahn), the survivor who helped keep her alive when she was stranded there and ultimately enabled her return to Silo 18.
Jimmy may now prove crucial to saving Juliette's home.
Meanwhile, the Before Times storyline takes a significant step forward. After episode seven ended with enormous drills boring into the ground outside Atlanta, episode eight finally gives viewers a proper look at the project being constructed there.
Per Stensen (Colin Hanks), the eccentric billionaire behind the operation, explains that 50 silos are being built as part of an extraordinary plan to ensure humanity survives an approaching catastrophe.
“We're facing the end of the world and it cannot be stopped,” he tells a stunned group that includes journalist Helen Drew (Jessica Henwick) and congressman Daniel Keene (Ashley Zukerman). “It can only be survived.”
The silos, Per explains, are not simply shelters designed to protect a fortunate few, but part of a plan intended to allow humanity to eventually repopulate the planet.
When Helen presses him on what exactly the silos are being built to survive, Per rules out nuclear war and/or another pandemic. Instead, he reveals, it's the very thing that made him the richest man in the world: nanotechnology.
Iran, he claims, has developed a weapon using the technology. The mysterious cloud encountered by Charlotte Keene (Jessica Brown Findlay) and her squadron during their disastrous mission to Iran was, according to Per, an example of nano warfare – finally explaining one of the Before Times storyline's biggest mysteries.
The revelation also dramatically reframes the world viewers have watched for three seasons. What has long appeared to be a toxic wasteland outside the silos may be connected to something far more sophisticated – and potentially more terrifying – than conventional warfare.
Helen, however, is far from convinced by Per's plans. After she challenges him, senator Rosalind Thurman (Laura Innes) reveals why Helen has been brought into the project: they want her to join them. As an incentive, she is offered what could be the story of a lifetime – the chance to become the first journalist to report on the silo project and, potentially, the end of the world itself.
Helen refuses, declaring that she would rather be “blown into pieces by a nuke”. She is later joined by Daniel, who has reached much the same conclusion, telling her he would rather “turn into goo” than spend his life underground with “cray-cray Stensen”.
Back in Silo 18, The Algorithm has discovered that Lucas and Kennedy survived, and instructs Camille Sims (Alexandria Riley) to determine the real reason they were sent to Silo 17.
Camille turns to her husband Robert Sims (Common) for answers, but he refuses to give her what she wants, further widening the divide between a couple who increasingly appear to be operating on opposing sides.
Silo season three, episode eight ending explained
While the Before Times finally explains why the silos exist, Juliette's storyline may provide the key to stopping Silo 18 from suffering the same fate as Silo 17.
Juliette remembers that the poisonous gas capable of killing a silo's entire population, called “the safeguard”, is delivered through a physical pipe – and, crucially, that the flow can potentially be stopped by sealing it.
Armed with a structural blueprint drawn by former IT chief Bernard Holland (Tim Robbins), showing how the silos connect back to Silo 1, Juliette attempts to replicate what she learnt in Silo 17 and block the mechanism threatening her own home.
But before she can carry out the plan, Juliette is arrested and taken into custody, where she discovers Robert has also been incarcerated. With both of them out of action, the fate of Silo 18 now rests with the remaining members of their group.
Episode eight therefore answers perhaps the biggest question Silo has posed – what drove humanity underground – while leaving another hanging over its final two episodes: can Juliette and her allies stop the system designed to destroy them?
