On Season 2 of Stranger Things, we finally got more of a glimpse into Eleven's origin story, and man, is it grim. What happened to Eleven's mom on Stranger Things is truly terrible. Spoilers head! After a particularly nasty fight with Hopper, who Eleven's been staying with since she escaped the Upside Down and he found her wandering the woods, Eleven finds a box in a hidden basement full of things Hopper copped from Hawkins Lab — including a file full of information on her. The file includes newspaper clippings about a mother, Terry Ives, who claims her daughter was kidnapped. (If you remember, Hopper found these clippings at the library last season.) So is Terry Ives Eleven's mom, and if so, what happened to her?
Eleven manages to use this information to identify her mother and track her down. She visits the same place Joyce and Hopper visited last season when they wanted to talk to Terry — and when they were told by her sister that they were "about five years too late" to try and talk to her. Terry was in a catatonic state then, mumbling nonsense words and not really being of any help to anybody, and she was the same way when Eleven found her.
When Joyce and Hopper found her last season, we got our first glimpse of the theory that Terry could be Eleven's mom. The show all but spelled it out for us with flashbacks of Eleven as Terry's sister talked about Jane, the daughter Terry lost. Terry's sister told them how she was involved with a drug study run by "the Man with a capital 'M.'" They'd give her psychedelic drugs and LSD, then put her into isolation tanks to run tests because they "wanted to expand the boundaries of the mind." Terry didn't know she was pregnant at the time she was participating in these studies, and her sister said she miscarried in the third trimester.
Except, of course, she didn't miscarry, and Terry always seemed to know this. She knew that Eleven — whose birth name we now can confirm is Jane — was still out there. When Eleven delved into her mind, she saw flashes of a baby being taken away from her, and Terry even kept a bedroom for her. "She keeps all of this up," Terry's sister told Joyce and Hopper last season. "Been doing it for 12 years. Terry pretends that Jane is real — like she's going to come home someday. Says she's special. Born with abilities."
Terry did try to get Eleven back early on, we've learned. She took a gun into the lab facilities, tried to sneak in covertly, and eventually pulled the gun and even shot a guard. She managed to locate the room Eleven was being held in before being detained and having her mind zapped to oblivion, apparently leaving her in this catatonic state, able to communicate with Eleven only through telekinesis. Terry also gave Eleven a glimpse of her "sister," another young girl who was in the lab with her. Eleven managed to find her, although that didn't go too well — but that's a different story.
Now, we know that Eleven did have a real family out there, and at least she can get some peace knowing that. The season ended by revealing that Hopper, who'd been caring for Eleven like his own child this entire season, managed to get a birth certificate stating that she is legally his daughter. This opens up a lot of questions: Sure, Eleven's mom isn't fit to care for her herself, but she does have blood relatives like Terry's sister, who even said she'd be more than happy to host her, making it odd that Hopper could so easily get custody. And also, how on earth did Terry know that Eleven had "abilities" when she's been catatonic for years and hasn't seen her since the day she was detained in the lab? Something tells me that we haven't seen the last of Eleven's family.