1. What happened to Will in the Upside Down?

The Monster captured Will and dragged him into the Upside-Down world, presumably to eat him. But when Will is discovered, he’s been pasted to the wall with something growing out of his mouth. After he left the hospital, we see in the last moments of the show that he coughed up something that has now escaped into our own world. So, what exactly happened to him after he was captured, and what did he bring back?

2.  What are Brenner and the Department of Energy trying to accomplish?

Brenner is apparently the scientist in charge of the facility under the guise of the Department of Energy. The DOE is the department of the government that primarily handles nuclear material. It oversees the nation’s nuclear weapons, energy production and waste disposal. It looked as if the program inadvertently created some people with special abilities, and Brenner’s research involved trying to figure out what they were capable of. When Eleven went into the tank, she saw a man speaking Russian. Maybe she was being trained to be a telepathic spy.

3. Why was Barb summarily killed off while Will got to return?

One of the things that really bothered me watching this season was how Barb got the short end of the stick when she was grabbed by the monster and killed off. It’s a shame, because she clearly meant a whole lot to Nancy. It also would have been easy for them to discover and rescue her, or switch the equation around somehow.

4. Who is Eleven / Jane’s father?

Throughout the show, Eleven refers to Dr. Martin Brenner as Papa. Is he really her father, or is that just something that she was conditioned to call him? If he was her father, there’s some seriously messed up things going on in his experiments, which makes him a bit creepier.

If he is her father, a whole new series of questions come up. When Hopper and Joyce visit Eleven’s mother, we learned that she had apparently miscarried in her third trimester — the birth was covered up by Brenner and his facility. How did they know Eleven was special? If Brenner wasn’t her father, who was?

5. Does Eleven have predecessors?

Her birth name was apparently Jane, but she goes by Eleven during the events of the show because of the tattoo on her wrist. What does the number mean? Is she the 11th person that they used in this particular program? If so, what happened to the first 10?

6. Is Brenner actually dead?

When the monster comes through the wall in the Middle school, it begins taking apart the armed soldiers Brenner brought along with him, and it jumps on him just as the camera cuts away. No one actually never sees exactly what happened to him, and without a body, he’s probably not dead.

7. Where did Hopper go when he left the hospital?

Right after Will was recovered and brought to the hospital, Hop leaves the room and gets into a car with two of Brenner’s agents, only to reappear later on. So, where did he go, and what was he up to? When he reappears, it’s clear that he didn’t make a bargain that sent him away or into prison — he’s still sheriff for Hawkins. So, what happened?

8. What happened to Eleven?

With the monster bearing down on them in the final episode, Eleven steps up and uses her powers to destroy the monster, and vanishes in the process. Everyone seems to think that she’s dead, except for Hop, who leaves some food in a box in the woods a month later, a ritual that he seems to have been doing for a while. The empty box would suggest that someone’s taking the food.