As fans will recall, the end of Season 3 was particularly rough for Eleven and Max. Eleven lost her powers during an epic face-off with the Mind Flayer, who assumed control of Max's brother Billy's body. The Mind Flayer needed to be killed, and Billy died trying from within to defeat the demon.

Max begins Season 4 of Stranger Things distraught over the death of her stepbrother. She's also become reclusive, breaking up with Lucas, not paying attention to her grades, and experiencing headaches and nightmares. When characters begin dying around them, the group discovers the headaches and nightmares are symptoms of a "curse" by Season 4's new villain: Vecna.

Vecna's "curse" invades the mind first, causing characters to hallucinate what they are most afraid of, then mentally traveling to the Upside Down, where Vecna confronts them, and they die. The group also later theorizes the "curse" targets people who have been experiencing deep hurt, like Max with her grief over her brother.

Afraid, but knowing the group hasn't figured out how to stop the curse, Max resigns herself to death. She writes letters to each of her friends to read after she's gone and reads her final letter to Billy's grave before the curse takes over. However, with the assistance of Lucas, Steve, and Dustin, Max escapes out of the Upside Down using music to defeat the curse.

When Max awakens, she's alive and continues to constantly listen to music in case the curse is still lurking. In the meantime, Max returns to her friends with a visual description of Vecna's lair in the Upside Down, which looks mysteriously like the old Creel House.