Early in the supersized finale of “Stranger Things 4” — or what would be roughly one-quarter of the way through a standard TV episode, but what’s less than one-tenth into the 140-minute “Chapter Nine: The Piggyback” — a stoner doofus stumbles into a two-pronged revelation. For plot purposes, Argyle (Eduardo Franco) thinks of the perfect place for Eleven (Millie Bobby Brown) to conduct her “mind fight.” His place of employment, Surfer Boy Pizza, not only carries the necessary amount of salt to better focus our hero’s powers, but it’s also got a bathtub-size container to help her travel into her friend’s mind.
But the more pertinent realization may belong to the audience. In case it wasn’t clear where “Stranger Things” Season 4 would stage its climactic battle, the term “mind fight” leaves no doubt. Eleven and One will square off in the same arena so much of Season 4 was set in: the human mind.