Well, we as audience members knew that, but the rebellious citizens of Silo 18 didn't have an inkling until the very end of the "Silo" Season 2 finale, "Into the Fire." And not so coincidentally, that's exactly where we leave Juliette and Bernard at the episode's conclusion.

The second Silo season finale turned out to be even more of a brain-scrambler than its first, if such an accomplishment can be believed. The futuristic dystopian saga based on Hugh Howey’s book trilogy clearly prides itself on its mind-bending,