'Stranger Things' season 2 spoilers, plot update: upcoming season to have new characters, more on the Upside Down

Promotional image for the Netflix series "Stranger Things."Facebook/strangerthingsTV

"Stranger Things" has easily become one of the best shows that debuted on the streaming service Netflix. This Halloween, the fan favorite series is coming back for its second season. It will welcome new faces and will delve deeper into the mysteries of the Upside Down.

With the season 2 premiere, "Aliens" actor Paul Reiser was reported last year to be joining the sci-fi/horror series as Dr. Owens. However, it has not been clarified whether his character will be good or evil. Also hopping in are "Goonies" and "Lord of the Rings" actor Sean Astin, who will be playing Bob, the local Hawkins RadioShack manager; and Danish actress Linnea Berthelsen, who will be portraying an emotionally damaged young woman named Roman. There are rumors that her character could have connections with Eleven (Millie Bobby Brown).

The intro music for "Strangers Things" has also become iconic since the show's first season premiered last year. The good news is that the creators of the track, Survive members Kyle Dixon and Michael Stein, are coming back to work on the music for season 2. The musicians recently sat down with Ars Technica and talked about the process of creating the soundtrack for the upcoming season of the popular Netflix series. "The Upside Down is weird and experimental, and we approached it with something like the 'Alien' soundtrack. But this music focused on the monster," Stein said.

Also talking about season 2, Dixon said, "There are new characters, fun, and the [Upside Down] will be more of a place — you'll spend more time [there]. So we'll make a lot more weird music this time around." And with how "Stranger Things" season 1 ended, it is evident that the show will be spending more time exploring the Upside Down and what mysteries the mystical location holds.

In other news, Netflix Chief Content Officer Ted Sarandos and co-founder Reed Hastings have apparently already seen the first episode of season 2. The bosses have recently spoken with NME about what they have seen, and Sarandos thinks it is "fantastic" and that it "delivers on everything that every fan wants."

"Stranger Things" season 2 premieres Oct. 31, on Netflix.