Silo Season 3 Review: Apple TV+’s Underground Sci-Fi is the Best it’s Ever Been

Apple TV+ has steadily carved out its spot as the premier home for big-budget sci-fi, and Silo remains one of its strongest shows. Season 2, however, ran into a problem that was hard to ignore. Stranding Juliette (Rebecca Ferguson) in a deserted Silo 17 while Silo 18 simmered through a half-baked rebellion meant neither storyline had enough momentum to carry an entire hour. We spent a lot of time watching Juliette tinker with rusted water pumps in near silence, before cutting back home to supporting characters whispering in dim corridors about an uprising that seemed permanently stuck in second gear.

Season 3 takes a very different approach. Juliette is no longer carrying the season on her own, and the show gets enough moving parts to keep its momentum going.

All 10 episodes of Silo Season 3 are now streaming on Apple TV+.

Here’s some quick context if you’re new to the show or bounced off after Season 2’s slog. Ten thousand people live inside a vast underground cylinder, raised to believe the surface is a toxic wasteland. Anyone who says they want to leave is given a cloth, sent outside to clean the camera sensors, and left to collapse in full view of everyone watching. Curiosity is effectively treason. Down below, there is no history beyond a heavily redacted governing text known as The Pact.

Multiple sub-plots keep things moving

What makes Season 3 work where Season 2 stalled is expanding the narrative into three distinct strands. Juliette’s amnesia arc, a paranoid political thriller set during the Before Times, and an escalating mystery unfolding in the lower levels.

The Before Times narrative, set three and a half centuries before the silos were built, follows Congressman Daniel (Ashley Zukerman) and and journalist Helen Drew (Jessica Henwick) digging into a mounting national security conspiracy. I loved this arc because we get to see what the outside world looked and felt like. The blue skies, open spaces and lush greens are a stark contrast to the claustrophobic industrial greys and ambers of silos and going back to the lower levels almost feels suffocatingly oppressive.

The backstory isn’t just distant lore, either; the show constantly bridges the gap through physical relics like Daniel’s watch or clues buried behind the flooded drill-pit door that make Helen and Daniel’s 21st-century investigation feel tangible in the present day.

We also get some key answers to how the silos came to be in the first place. Who saw the collapse coming, why silo shafts were built in secrecy and where the rules the silos live by originate from. And allusions to something we’ve all been curious about, is the outside in present-arc inhabitable or is Silo 18’s intelligence full of B.S.?

Big ideas, personal stakes

One of Graham Yost’s biggest strengths as showrunner is his ability to take high-concept sci-fi ideas and keep them tied to individual characters. Some of the big ideas and themes explored this season are memory, identity and control. Season 3 could easily get bogged down with lore-dumps on the mechanics of memory suppression but generally keeps those ideas anchored to Juliette and the people around her.

We don’t get an explainer on what memory engineering is or where it came from. But we do see what happens when Juliette can no longer rely on her own recollection of events and questions whether she can trust the person handing her a cup of tea as she battles with her sense of self. Ferguson portrays this particularly well with intensity and her signature tightening of her jaw and well-timed fist clenches. It also suits her character. Juliette has never been particularly interested in telling people what she thinks before she’s figured it out herself, and the uncertainty around her memories makes that instinct even more pronounced.

Her amnesia does start to drag a bit in the first few episodes, particularly when Juliette circles around information viewers already have. And it’s where the pacing starts to fall in the Season 2 slog-fest territory. But later episodes make it make more sense and give her confusion more context, tying it into the season’s ideas about identity, memory, and control. Silo knows exactly what information it wants to hold back, and there are moments when you can feel the show deliberately making Juliette take the long way around. It’s also where I felt the multiple story lines had trade-offs where one story line moves faster and you have to survive slower scenes to get back.

Down and Out in Silo 18

Beyond Juliette, the supporting characters get considerably more to do this season. Robert Sims (Common) remains one of the smartest additions made by the adaptation, having been largely invented for the series rather than taken directly from Hugh Howey’s books.

His relationship with Camille (Alexandria Riley) gives the season some of its strongest psychological tension. Sims has spent years working inside a system built around controlling information, so watching that relationship start to break down at home gives Common plenty to play with. He gives his best performance of the series so far, particularly as Sims begins to realise that the methods he’s relied on for years aren’t enough to keep his own life under control.

But Camille isn’t just along for the ride. Her solo scenes in the Vault are easily some of the best stuff in the season. Watching a master of human manipulation step into the dark to out-think an omniscient AI that picked her specifically for her cold pragmatism turns her arc into a fantastic, low-key battle of wits.

Elsewhere in the Down Deep, Sheriff Paul Billings (Chinaza Uche) and Hank Murphy (Billy Postlethwaite) bring a noir, buddy-cop dynamic to the mystery-of-the-season untangling Judicial cover-ups down dark corridors with flashlights, bad coffee, and zero modern forensics. 

Further down below, Knox (Shane McRae) and Shirley Campbell (Remmie Milner) run Mechanical like an underground union strike. Their high-stakes rebellion gets grounded in brutal day-to-day logistics of organizing a rebellion. There are supplies to move, barricades to build, people trying to keep things running and, increasingly, not enough of anything to go around. It affects how people eat, work and move around the silo all the while creating a sense of claustrophobic pressure that makes the entire 144-level cylinder feel like a fuse burning at both ends.

Should You Watch Silo Season 3?

If you bounced off Season 2’s sluggish middle stretch, Season 3 is the exact course correction you were hoping for. Expanding the canvas into three distinct storylines gives the show the breathing room and momentum it desperately needed, turning the show’s stagnant dark grimy corridor drama back into a propulsive sci-fi mystery.

While weekly drops might make the middle-stretch amnesia drag feel a little testing, watching all ten episodes back-to-back allows those parallel threads to lock together seamlessly. The finale won’t hand you a clean bow either. It leans heavily into setting up the show’s fourth and final season, but the journey there is sharp, lore-rich, and deeply rewarding. Silo is officially back on top of its game, and cements Apple TV+ as the go-to home for heavy-hitting TV sci-fi.