The hit sci-fi series Silo is back today for a third season, streaming exclusively on Apple TV. Based on the book series by Hugh Howey, the acclaimed series sees the human population living in a vast underground bunker, but no one really knows how it came to be. In the third season, a split timeline narrative begins to reveal some of the show’s biggest mysteries. In the present timeline, Juliette (star Rebecca Ferguson) struggles with amnesia, while in the past timeline, flashbacks show who, how and why the silos were built in the first place.