The latest clue to Stranger Things season 5’s plot is a missing poster for Eleven/Jane Hopper (Millie Bobby Brown), but now the biggest question is why Eleven has gone missing. Since the release of its first season in 2016, Stranger Things has been one of Netflix’s biggest and most popular titles. Its combination of horror, fantasy, drama, and 1980s nostalgia has captured the attention of viewers of different ages, who have followed the story of Eleven and the rest of the Hawkins crew as they try to solve the mysteries of the Upside Down.

After the massive cliffhanger at Eleven going missing, though the reasons for her disappearance are unknown – however, there are already a couple of theories about this.

5 Colonel Sullivan Is The One Looking For Eleven

Sullivan’s People Might Be Behind Those Missing Posters

A new enemy introduced in Stranger Things season 4 is Lt. Colonel Jack Sullivan (Sherman Augustus), a high-ranking career officer in the US Army Criminal Investigation Command. Sullivan knows about Eleven’s existence and believes she has been the one committing horrific crimes across Hawkins. Because of this, Sullivan planned to neutralize her, and he and his team eventually made it to the Nina Project. Despite attacking the facility and killing Brenner, Sullivan couldn’t neutralize Eleven, who, instead, crashed his helicopter, but he survived.

Sullivan could have ordered the search for Eleven by making people believe she’s missing, so Hawkins’ residents would be the ones who find her for him.

Sullivan has even more reasons to go after Eleven after seeing what was inside the Nina Project and witnessing Eleven’s powers. Sullivan now knows how dangerous Eleven can be, and he’s not going to risk his people anymore. Instead, Sullivan could have ordered the search for Eleven by making people believe she’s missing, so Hawkins’ residents would be the ones who find her for him.

4 Eleven Isn’t Missing – She’s Hiding

Eleven Would Have Strong Reasons To Hide For A While

Eleven hasn’t had a real moment of peace in her life, as she became a Hawkins Lab subject the moment she was born, and she has been running away from something since then. With this in mind, it wouldn’t be surprising if she goes into hiding in Stranger Things season 5, for her safety and that of her loved ones. This wouldn’t be the first time Eleven has to hide, as she did so in season 2 when Hopper took her in after finding her in the woods following her disappearance at the end of season 1.

Stranger Things season 5 could repeat this, but the reasons for Eleven going into hiding could be many. As mentioned above, there’s Sullivan and his people going after her, as well as Vecna, and as Hawkins is a small town, there could be rumors about Eleven that could force her into hiding.

3 Eleven Left To Find Kali

Eleven Will Need All The Help She Can Get Against Vecna

Eleven is about to face the biggest challenges and battles in all of Stranger Things’ history, so she’s going to need as much help as she can get. In season 2, Eleven’s “sister”, Kali (Linnea Berthelsen), a fellow Hawkins Lab subject, was introduced. Kali has the power of inducing mental hallucinations in her targets, and in season 2, she helps Eleven master her powers. Unfortunately, Kali hasn’t appeared again in Stranger Things, nor has her fate been mentioned, but she could return in the final season as an ally.

Eleven’s powers, along with Kali’s, could be key to finally defeating Vecna, who shares all those powers with them. Eleven could become aware of this and set out to find Kali, though without telling any of her friends and family, thus launching a search for her while she’s already far from Hawkins, looking for her sister.

2 Eleven Is Lost Due To Time Travel

Eleven Could Be Lost In Time

A big theory about Stranger Things season 5 is that it will include time travel, although exactly how and why is unclear. If it happens, this could be the reason for Eleven’s disappearance. Eleven could go back in time to stop key events from happening, thus saving Hawkins and her friends. Of course, this trip would take at least a couple of days, and Hopper and Joyce might not be aware of what Eleven is doing. Time travel could be a project by Brenner and/or Owens, hence the secrecy and why Eleven wouldn’t tell anyone about it.

1 Vecna Took Eleven To The Upside Down

Eleven Could Be Trapped In The Other Dimension

The most popular idea around Eleven’s disappearance in Stranger Things season 5 involves Vecna. Eleven might be trapped in the Upside Down, either because Vecna took her or she ventured into the other dimension to face him and can’t find a way out. Vecna and Eleven’s reunion and final battle are some of the most anticipated moments in Stranger Things season 5, as it’s not going to be an easy battle for either of them. While the Hawkins crew deals with challenges and issues in the human world and looks for Eleven, she could be fighting for her life in Upside Down.