As Eleven regains her strength and breaks through security, she confronts Kay and tries to kill her telekinetically, but fails due to the lingering effects of the inhibitor. Hopper lowers the room's temperature to weaken the vines, allowing him to escape restraint and incapacitate Kay. During the escape, Eleven accidentally exposes a bomb hidden under Hopper's jacket, prompting an emotional confrontation when he insists on sacrificing himself. She refuses to abandon him and pursues him through the facility until Hopper suddenly returns, having changed his mind after encountering someone unexpected.

Hopper steps aside, revealing the survival and return of Kali Prasad marking a major reunion and shift in Eleven's fight against the Upside Down.

In the series finale, Eleven confronts Vecna in both his mind and the real world while her friends fight and kill the Mind Flayer. For the mind part in an isolation tank, Eleven goes barefoot and wears a spring wetsuit as she takes Max and Kali into the mind. This lasts until Vecna tricks Hopper into destroying the tank. Using his own recently developed telekinetic abilities, Will restrains Vecna, allowing Eleven to fatally impale him before Joyce finishes Vecna off with an axe. As the Upside Down is destroyed, Eleven seemingly remains behind to die so as to ensure that the military can never use her to create another Henry Creel, saying a final telepathic goodbye to Mike. Eighteen months later, and after having a realization during his high school graduation that Eleven could not have used her powers to enter his mind while under the effects of the military's sonic weapons, Mike relates his theory to his friends that Eleven survived and that the dying Kali used her powers to project an illusion of Eleven's death while she escaped undetected. His friends profess their belief and hope in Mike's theory that she escaped and found somewhere to settle down peacefully. While Mike is explaining his theory, footage is shown of Eleven with a ponytail as she hikes towards a town near three waterfalls.