Everyone thinks "Stranger Things" Season 4 is about trauma. It’s not

Atantalizing two-word phrase handwritten in pen on a sheet of high school stationery seems to offer the key that unlocks the mysteries — both psychological and supernatural — of the first half of the fourth season of "Stranger Things."

Dustin (Gaten Matarazzo), Lucas (Caleb McLaughlin), Steve (Joe Keery) and Max (Sadie Sink) have broken into Hawkins High and are rifling through the files of the school psychologist trying to figure out if there is any connection among the victims of Vecna,

he season's snake-veined big bad whose favorite pasttimes include antiquing (that grandfather clock is a real find) and gruesomely mangling the bodies of children as he sucks out their souls. As Max spreads the victims' files out on the darkened desk

a pattern emerges. All had sought counseling for a common set of symptoms, including nightmares, headaches, and nosebleeds. But the kicker comes at the bottom of the page, underlined twice: "past trauma."