Be warned, this article includes some fairly major spoilers for season two of ‘Stranger Things’. So if you haven’t finished the season yet, bookmark this article and come back when you have.

As the second season of ‘Stranger Things’ unfolded on Netflix over the weekend, viewers were in for their fair share of surprises. Arguably the most unexpected, though, came in the form of the season’s divisive seventh episode. Dubbed ‘The Lost Sister’, that episode took a break from the main plot to follow Eleven as her visions lead her to Chicago, where she finds another of the psychic children who served as test subjects at the Hawkins Lab.

Taken on its own, the episode could be seen as an experiment (series co-creators the Duffer Brothers have already described it as such) or even just an odd one-off. But there may be more to it than that. According to producer Shawn Levy, ‘The Lost Sister’ in some ways represents a small taste of the show’s future. Not in terms of characters, necessarily, but rather in terms of setting and mythology. The possibility of the show expanding beyond its small-town setting in Hawkin has been discussed as a possibility for future seasons, with Levy dryly pointing out that “There’s only so much evil that can happen in that lab.” Additionally, there is a clear interest in further exploring Eleven and her psychic “siblings” from Dr. Brenner’s lab.

And speaking of Brenner, ‘The Lost Sister’ suggested (though not conclusively so) that the good doctor was still alive, despite his apparent death at the hands (err, claws) of the Demogorgan at the end of the first season. As Levy explained in conversation with Collider:

“We took a big swing for instance to open the show with a car chase in another city, then Episode 7 goes to another city for an entire episode. Whether or not people feel that episode was entirely successful, the Duffers want to take some swings and they know that they’re not going to please everybody. But that feeling of the world getting bigger especially coupled with the fact that it now seems clear that Brenner is alive, Brenner is out there. I for one think that that one scene with Modine and Millie in Episode 7 is one of the juiciest scenes, and it kind of brought me back to how haunting Modine is in that Brenner role.”

Both seasons of ‘Stranger Things’ are currently available to stream on Netflix. The show’s acclaimed cast includes Winona Ryder, David Harbor, Finn Wolfhard, Gaten Matarazzo, Joe Keery, Natalia Dyer, and Millie Bobbie Brown.