Stranger Things is about to air its final episode, which will take place on New Year's Eve. It will feature an epic confrontation against Vecna and the Upside Down. There are many unanswered questions in the show's plot prior to the conclusion of Stranger Things.One of these mysteries stems back to the very first season. In Episode 1, a door opens to Will Byers' home shortly before he is captured by Demogorgon, leaving fans perplexed for years regarding how the door was opened. Recently, the comments of the show's creators led fans to theorize that a member of the team may betray their friends during the last episode.The reason for this question has an impact on understanding how events transpired in Stranger Things. According to one of the Duffer Brothers, Demogorgons do not possess a psychic ability. Therefore, if the Demogorgon did not have the ability to open the door, it must have been another entity with mental ability that did so. Thus, it is theorized that a person with psychic powers was part of the original betrayal.The Duffer Brothers also revealed that the solution to this riddle will be presented in Stranger Things Season 5. This has many fans speculating whether or not someone trusted may turn on one of the other team members, with all indications pointing to their level of trust being true.Let's look at the ideas fans have shared, what might be behind them, and why some people think one of the main characters could have played a part in that early moment or in a new twist at the end of the series. All of these ideas are just theories, but they come from the clues Stranger Things has dropped over many seasons.Old mystery from the first episode of Stranger Things still mattersThe first episode of Stranger Things shows Will Byers running home and hiding in a shed. Just before this, the door to his house opens itself. At the time, most people thought this was just something the Demogorgon could do. The creature looked strange and powerful, so it made sense in the moment. But many people did not question it too much back then.It has been confirmed by the Duffers that Demogorgons cannot psychically control objects, which was the answer to a multitude of questions created when Demogorgons first appeared. Because they cannot manipulate objects using their minds, this suggests that someone, presumably with psychic powers, opened the door when the Demogorgon came. Therefore, it begs the question of who that "someone" is, and for what purpose they did so.Clarifying who opened the door is important due to the ongoing history between the Stranger Things franchise and psychic abilities, which have been portrayed throughout the entire series. Eleven has been established as a character with very strong psychic abilities. The powers of El have allowed her to defeat many different enemies, close many portals between the human and Upside Down dimensions, and experience all of the feelings of the other characters in the series through each of their emotions. Because of her extremely powerful psychic abilities, many fans are debating whether she opened the door or not (either intentionally or without knowing) when the Demogorgon came through.This idea makes some viewers uncomfortable. Eleven has always been seen as a protector of her friends. Thinking that she might have played a role that put Will in danger feels like a betrayal. But not all fans think she did it on purpose. Some think that if she were involved, it might be because she was not fully in control of her powers at that time. In her early days as a child with powers, she was confused, scared, and still learning what she could do. View this post on Instagram Instagram PostOther fans think that Vecna, the villain of Stranger Things Season 5, could have reached into Eleven's mind. Vecna has strong mental powers, and he has shown the ability to influence others. In earlier episodes this season, he made Will see visions and feel trapped in a hidden world inside his mind. Because of this, some fans think Vecna could have forced Eleven to open the door.This idea brings up the possibility that Eleven might not have chosen to help Vecna. Instead, she might have been controlled or influenced by him in some way. This would make her not a willing betrayer, but more like someone caught in a larger plan.Other Stranger Things fan theoriesNot all theories point to Eleven. Some fans think another character with psychic power could be involved. Over the seasons, other kids and adults have shown hints of power or a strange connection to the Upside Down. Some fans look at these smaller clues and wonder if someone else might have done it.Several other fans place less emphasis on powers and more emphasis on motivation. Some fans believe that all loyalty and commitment will endure, maintaining that there won't be a significant betrayal.The Duffers have promised that the finale will answer many questions, and this includes the mystery of the unlocked door and all the hints about power and control. Whether the answer involves betrayal or not, fans are clearly excited to finally see how the story closes.