The episode follows a high-stakes, multi-front battle to stop the powerful entity from opening a permanent gate between the real world and the Upside Down .

: Simultaneously, Hopper, Joyce, and Murray break back into the Soviet prison to destroy the captive Demogorgons and "The Shadow" particles, weakening the hive mind to assist the kids in Hawkins. Key Plot Points and Outcomes

: The title refers to Eleven using a sensory deprivation tank (improvised from a pizza dough freezer) to "piggyback" into Max’s mind to fight Vecna psychically from Nevada.

: The Hawkins group executes a four-phase plan: Max acts as bait to lure Vecna into a trance; Dustin and Eddie distract the "demobats"; and Nancy, Steve, and Robin enter the Creel House in the Upside Down to kill Vecna's physical form.