"The first five minutes, you're not going to know you're watching 'Stranger Things,'" the actor, who plays Sheriff Jim Hopper, tells THR.

Viewers already know the Demogorgon. What other monstrous creatures lurk inside the Upside Down?

In a few months, viewers will have the answer, as Stranger Things is set for a second season debut on Netflix just in time for Halloween. The Comic-Con trailer offered its fair share of glimpses into the darkness ahead, most of which seems to stem from Will Byers (Noah Schnapp) and his weeklong stint inside the bleak dimension his friends not-so-lovingly dubbed "the Upside Down." But as for the overarching story and any new threats facing the Hawkins kids in season two? For now, mum's the word.

With that said, while viewers don't know what exactly the new episodes will contain, we do at least have a sense of what season two's very first scene will feel like. Speaking with The Hollywood Reporter, actor David Harbour (who received an Emmy nomination for his turn as Sheriff Jim Hopper) said that he recently watched the opening scene during a visit to the show's editing room. He stopped short of painting a vivid picture of the scene, but his description makes it apparent that the show will begin in unfamiliar territory.

"The first five minutes, you're not going to know you're watching Stranger Things," said the actor. "You're going to be checking the thing: 'Did I put on something else?' Then something happens in the last part of those five minutes where you realize we've opened up the world in a fresh new way, and we introduce some new concepts."

It's almost a dated reference at this point, but Harbour's description brings up memories of the Lost season two premiere's first scene. After spending the entire summer wondering what was inside the hatch, the show began with a cold open that seemed entirely unconnected to the overarching mythology, before making its connection to the greater Lost narrative immediately known. If Stranger Things season two follows a similar path, then it should be a very disorienting launch point indeed.

As for the new concepts Harbour teased? He would only offer up this hot tip: "It's things the fans have mentioned and have been talking about. I don't want to bring up what those are specifically, but we delve into questions that you guys had about the past histories of these people. It really opens up the world, and then the whole world is able to get bigger and darker and weirder. I think people are going to be really blown away."

Watch the video below for more from Harbour on Stranger Things and his upcoming stint as Hellboy:

Stranger Things returns Oct. 27. Follow THR.com/StrangerThings for our coverage of the show.