Back story! Angst! Time travel! Creative and grotesque ways to take down super-powerful demons! Tonight’s episode of Supernatural had it all, harking back to fan-favorite episodes like “In the Beginning” and “The Song Remains the Same” that brought Sam and Dean face-to-face with younger versions of their parents.

SPOILER ALERT: Read no further if you haven’t seen the Jan. 30 episode, “As Time Goes By,” and if you want to stay away from teases about the rest of season 8.

“As Time Goes By” took us to the past with some new back story about John Winchester and his father, Henry, but it is also an episode that’s launching Supernatural forward, with a new addition to the show’s mythology, the Men of Letters, a secret organization that approaches the world of the supernatural as knowledge to record rather than creatures to defeat.

In addition to learning more about this organization, Sam also learns (via ill-fated former member Larry) about a bunker that, according to executive producer Robert Singer, becomes something the road show has never had before: a home base.

“It’s a really stunning set. It’s full of mysteries,” Singer told reporters earlier this week. “After eight years of never having a home base, this will be home base for quite some time.”

The boys’ new home, abandoned decades ago by some of the last Men of Letters, contains loads of knowledge the organization collected – which once-law-school-bound Sam, of course, will geek-out over. (Dean, meanwhile, will just happy to have his own room and plaster it with posters, Singer revealed.)

The line of Men of Letters has died out, so Sam and Dean have the place to themselves and aren’t about to reveal the house of valuable secrets to a bunch of other hunters, but Singer said half-jokingly, “I would be surprised if Garth didn’t show up and probably break an expensive globe.”

Singer also noted that the boys have moved past their clashes over Dean’s friendship with Benny and Sam’s desire to give up hunting. But this is Supernatural, so there’s still new drama brewing in the episodes ahead. Singer said there will be “new conflict” between the boys “for a different kind of reason, for something that they didn’t see coming. Really starting next week, that thing will carry through to the end of the year.”

And though Sam and Dean have found some peace with one another after the tension over Benny and Amelia, that doesn’t mean we’ve seen the last of those characters. Dean’s resurrected vamp buddy will definitely be back – “We never felt that that story was totally ended. It’s probably not great drama to end a whole arc on a phone call,” Singer said – and Amelia could see a return too, the EP teased.

Also definitely returning before the end of season 8: Castiel and Charlie — but this time, Felicia Day’s techie girl-on-the-run will bring a case to Sam and Dean.

For more on tonight’s episode, read what Singer had to say about the Winchester boys’ meet-up with their time traveling grandfather. And come back to EW in the morning for a recap of the episode.

Follow Emily on Twitter: @EmilyNRome