In the wake of HBO’s “Game of Thrones,” the biggest television show left standing may be a show that isn’t on traditional TV (and therefore doesn’t get rated by Nielsen). For the moment, anyway, nothing feels like it has more big-tent appeal than Netflix’s energetically spooky sci-fi drama “Stranger Things,” whose eight-episode third season arrives with a patriotic flourish on Thursday. (A Fourth of July fair figures prominently in the plot.)

But much of the appeal of Matt and Ross Duffer’s series has always been its lack of grandiosity or pretension, its disdain of the kind of mock gravitas “Thrones” embraced. The Duffers just want to scare us and charm us, to indulge their love of science-fiction and horror tropes and to perfect the pop-cult simulacrum of 1980s Midwestern America in which their show is set.

The mission hasn’t changed in “Stranger Things 3,” which takes place in 1985, a year after the events of the second season (just as the second season took place a year after the first). The extent to which you’ll be scared or charmed may be variable, though. As happens in the film world — and no show more authentically embodies the notion of the series-as-eight-hour-movie — “Stranger Things” is already showing some franchise fatigue.