No one is allowed to leave the Silo, but if they want to, they can. Very rarely does someone decide to leave. They get a spacesuit and are taken to the surface. One character makes this journey, and like everyone else, collapses after a few minutes outside, all in full view of the cameras, accompanied by the population. It's not clear who built the Silo. The History of the Silo only goes 140 years into the past, when a rebellion erased all records of the previous civilization.
In Silo, our protagonist is Juliette Nichols (Rebecca Ferguson), an engineer who becomes sheriff due to a series of violent circumstances and uses the opportunity to try to shed light on the death of her ex-boyfriend, a questioning man who may have upset the powerful in his search for the truth.
It seems that we've already seen this in other works of the genre. But in Silo we don't have shabby people, sickly children and widespread hunger, as is usually the case in this type of movie. Silo has agricultural and agrarian areas, everyone has food, water and electricity. For dramatic purposes, they just don't have elevators, the people on the upper floors don't mix with those on the lower floors, purely for geographical reasons.
Nor is there an oppressive dictatorial society, although there is an imbalance between the powers and the Judiciary is frowned upon by the other powers and by the population, with a Judge, head of the Judiciary, even confronting the Mayor, and yes we are still talking about the fictional series.
There's no sense of urgency to leave the Silo, it's a rigidly controlled society in some respects (birth control, for example, which is understandable). The protagonist is driven much more by curiosity than necessity, and we're along for the ride. Visually, Silo had all the makings of being claustrophobic and monotonous, but features like placing large screens on every floor showing the exterior, even if it's desolate, give it the feeling of a spaceship rather than a building. Which is pretty cool.
Silo is a post-apocalyptic mystery series, it avoids the biggest clichés of the genre, it doesn't have artificially unsympathetic characters, and above all, Rebecca Ferguson's character Juliette isn't a "Mary Sue", she's not the right person who never makes a mistake and wins everything on a plate.
I haven't read the books yet, but as far as I know they are chronologically different from the presentation of the series, which seems to be leaner, at least in this initial arc. I'll be reading the books very soon so that I can see the differences more clearly.