Elements of “Stranger Things ,” that make the show worth watching. Mild spoilers not exceeding Chapter Two of the second season.

“Stranger Things 2” became available on Netflix Friday, Oct. 27. The year is 1984 and the setting: a mysterious midwestern town called Hawkins, Indiana.

It’s been 300 days since we last glimpsed the town’s residents, but after an emotionally draining season one wrap-up, the only number that really matters is Eleven.

The Duffer Brother’s hit series found critical acclaim through Netflix in 2016, attracting viewers with its good-hearted characters and fiercely dark sci-fi action. In season one, a gang of young people are exposed to a toxic parallel of their rural community — the “Upside Down.”

Eleven made her escape from the cruel experiments at Hawkins National Laboratory, but disappeared in the season’s finale, after showing the true potential of her telepathic abilities.

But that’s enough summary for now.

Season two keeps up the ‘80s pop culture gold while raising the ante for character development, depth and shaking imagery.

Will, who spent most of season one trapped in the Upside Down, is sought by a sort of smoke-shadow-and-lightning-strikes-giant-spider figure that is altogether terrifying.

His friends are there though, just when doom is most near. These scenes bring to mind the urgency of Hawkins other-worldly dangers and the significance of the gang’s “Stand by Me” determination.

Some interesting new characters are mixed into the heavy plot, including an investigative conspiracy theorist and a would-be villain in a lab coat. A violent heist scene drops us into season two and reveals that there are others like Eleven, a detail that is sure to become crucial.

Other Hawkins newcomers include Billy —a mean-spirited mullet in a Camaro — and his younger sister Mad Max. Max is a dominant arcade gamer and the gang takes notice, so much so that they invite her to join when they trick-or-treat.

Though the Netflix series is consistently spooky at it’s core, Chapter Two of “Stranger Things 2” is a true Halloween episode.

In full “Ghostbusters” regalia, Mike, Will, Lucas and Dustin have a coming-of-age moment when they are the only ones to wear costumes to school. But their gear, based on the 1984 movie starring Bill Murray, seems well-suited for that night’s tasks.

While the gang solicits candy at evil’s front door, some of the high school characters celebrate the holiday with “pure-fuel” punch and AC/DC. Meanwhile Police Chief Hopper takes a vested interest in the suspicious activity at Hawkins Labs.

Consistent with last season’s approach, “Stranger Things 2” pushes tensions to a point of inevitable eruption. The Upside Down draws ever nearer to the real world, but the show has reportedly just scratched the surface of the Duffer brothers’ universe mythos.

The second season promises at least some answers though, about Eleven’s past and the intentions of Hawkins National Lab. For now the most difficult question to ask is how will our characters possibly overcome (or even simply survive) the shadowy destruction at their doorstep? If the protagonists do not soon inherit some “Walking Dead”-style vigilantism, no one will be around for a third season.