
Fans can breathe a sigh of relief: Season 2 of Stranger Things aired, and things in Hawkins are actually not that terrible (spoilers ahead!). Eleven—who now goes by Jane—has closed the gate to the Upside Down and reunited with the gang in the season finale. And the happiest news of all? Hopper is now officially Jane's legal father.
After keeping her in hiding and acting as an unofficial guardian all season, Hopper obtained adoption papers via Dr. Owens, the former head of the Hopkins National Laboratory. (It's not clear how Dr. Owens got such papers, but it probably wasn't legal.) But hold on: Doesn't this kinda, sorta confirm the popular fan theory that Eleven is Hopper's daughter? Technically, she is his daughter now! OK, OK, that's not exactly what the theory was.
Viewers learned in season 1 that Hopper once had a daughter, Sarah, who died of cancer at a young age. But some fans believe Hopper's memories have been altered by Hawkins Lab, making him think his daughter died when in reality she was stolen for experimental purposes. And these fans believe that daughter is actually Eleven. This two-part video series lays out a pretty convincing argument for that theory:
Now, with the new information from season 2, it's looking less and less likely that the second part of this theory—that Jane is Hopper's biological child—is true. (Though we still don't know who Jane's father is, so it's possible!) But it is looking overwhelmingly like the first part of the theory is true.
Here's why: In season 2, episode 7, we meet Jane's "sister," Kali. Kali is another child victim of the Hawkins lab with special powers. She can make people see things that aren't real—meaning any past information we've learned could have been illusions all along. Hawkins Lab could have easily harnessed this power to make Hopper see the death of his child, which we saw in a fuzzy flashback in season 1. Kali herself seems a little old to be Hopper's daughter, but she's labelled as "eight," so there are at least nine other children out there we haven't met.

It seems highly likely that Hopper's daughter Sarah was one of the many stolen by Hawkins Lab. Unfortunately, we'll have to wait until season 3 to find out for sure. Netflix has renewed Stranger Things for a third season, but no release date has been announced yet.