Silo Season 3, episode 7 finally reveals who built the silos

It's all starting to come together.

One of the core mysteries throughout Silo has been where the giant underground cities came from, and why they were built.

Now, seven episodes into the third season, we still don't know the why — but we're starting to get a sense of the who .

SEE ALSO: 'Silo' Season 3, episode 5 ending explained: Who is Per Stensen? What happens at the end of Silo Season 3, episode 7? Congressman Daniel Keene (Ashley Zukerman) and journalist Helen Drew (Jessica Henwick) have been on a strange journey so far in Season 3's flashback storyline.

They've dug into what happened to Daniel's sister Charles (Jessica Brown Findlay) on that Iran mission , been followed by a mysterious gray-haired man , and even had their car take on a life of its own to essentially kidnap them.

Finally, though, episode 7 seems to bring some answers.

After their autonomous vehicle abduction, they're met by Senator Thurman (Laura Innes), who introduces them to the billionaire they were discussing at the end of episode 6, Per Stensen (Colin Hanks).

Stensen tells them they'll get all the answers they crave if they sign a simple NDA.

"Once we've signed, you'll get on the plane, and this time tomorrow you'll know everything," says Senator Thurman.

Once the plane lands in Atlanta, Georgia, Stensen tells Helen that the next leg of the journey will be via helicopter.

She asks where they're going, and he tells her a property of his.

"It's 300,000 acres," says Stensen.

"That's 400 square miles.

It used to consist of 42 individual farms." In the episode's final scene, we finally get a glimpse of what they're going to see.