Apple TVPost-apocalypse shows vary according to the apocalypse itself. In Fallout, it’s a nuclear blast that creates a wasteland. In The Last of Us, it’s a virus that turns people into zombies. In Snowpiercer, it’s a climate crisis. But Apple TV’s Silo is a little different. In Season 1, we were introduced to Juliette (Rebecca Ferguson), a resident in an underground silo where the inhabitants have no memory of what put them there — they only know that it’s not safe inside. In Season 3, we’re finally learning about the silo’s origins in a series of flashbacks to the “Before Times.” As journalist Helen Drew (Jessica Henwick) and Congressman Daniel Keene (Ashley Zukerman) investigate a strange occurrence during a Navy mission, they eventually stumble on a vast conspiracy involving trillionaire Per Stensen (Colin Hanks). In the penultimate episode of the season, we finally get some answers from Per — and they reveal the reason the silos were built in the first place. Warning! Spoilers for Silo Season 3 Episode 8, “Gray Goo,” ahead!Per Stenson and Senator Thurman try to recruit Helen and Daniel to their cause. | Apple TVAfter having their car hijacked, Helen and Daniel are brought to Georgia, where Per Stensen and Senator Thurman lay out exactly what they’ve been fighting in secret: nanotechnology. Charlotte’s mission was to take out a nanoweapon facility in Iran, but they ran into a cloud full of nanoweapons that took over her plan in seconds. But apparently, there was a contingency plan.“Your friends, Daniel, in the Army Corps of Engineers spent two years digging a 75-mile tunnel from Turkmenistan to right below the Iranian facility,” Senator Thurman’s daughter Anna says. “The second your squad came under attack, we blew up their facility with a low-yield nuclear weapon.” That’s why Per is secretly building the silos, as a contingency plan for when this nanotechnology goes global. Helen is skeptical and asks why he doesn’t use his money to cure cancer or solve world hunger, and it’s then that Per reveals that nanotechnology isn’t the only motivation for this project; it’s just one of many. Ultimately, Helen and Daniel choose to turn down the offer. | Apple TV“Could I stop this with money? Maybe buy Iran,” he says. “Would we be safe then? I mean, safe from Iran, but not from the troll who lives in his mother’s basement who decides he wants to hack into missile command and launch WWIII, or release a virus that he made with Crispr, or God forbid, make a nanoweapon for $300 and turns you and everyone else on the planet Earth into gray goo. Any one of these is the end of our species.”Stensen and Thurman try to bring Charlotte, Helen, and Daniel into the fold, and while Charlotte takes them up on it, Helen and Daniel choose not to. “If somehow you’re right about the end of the world, I think I’d rather be blown to bits by a nuke or turn into gray goo by nano than stick around for your post-apocalyptic underground mole-people party,” Helen says.Per’s motivations may seem like just a doomer attitude from what is obviously an Elon Musk analog, but what it’s really doing is setting the stage for the reveal Silo fans have been waiting three seasons for: which one of these “gray goo” scenarios is the one that actually happens in the future. With one episode left in Season 3 and Season 4 being the final season of the series as a whole, it’s only a matter of time until we find out. It’s likely the Season 3 finale will solve this big mystery, but it will only open up a new one for Season 4: how does this project tie into what Juliette and the rest of the Silo dwellers are experiencing in the future, and what will happen to Helen and Daniel since they turned down a chance at survival from a catastrophic event we know will happen?Silo Season 3 is now streaming on Apple TV.