Max is in grave danger... and running out of time. A patient at Pennhurst asylum has visitors. Elsewhere, in Russia, Hopper is hard at work.

As Hopper braces to battle a monster, Dustin dissects Vecna's motives — and decodes a message from beyond. El finds strength in a distant memory.

Nancy has sobering visions, and El passes an important test. Back in Hawkins, the gang gathers supplies and prepares for battle.

With selfless hearts and a clash of metal, heroes fight from every corner of the battlefield to save Hawkins — and the world itself.