Probably-unnecessary warning: If clowns scare you, you may not want to watch this.

The upcoming adaptation of Stephen King's classic IT has horror-movie fans excited like they haven't been in years, and much of that is due to just how terrific -- and terrifying -- the trailers have been.

This one is the third Warner Bros. has released (here's the first and the second), and it opens up the wider story much more than the previous two. We all know IT is about an evil clown that murders children (if you didn't know that, well, now you do), but there's a lot more to it than just that.

The town of Derry, Maine, has suffered an inordinate amount of massacres and tragedies over the years, decades and even centuries. The thing is, that's no secret. The people of Derry know this -- and choose to ignore it -- which is something the main characters discover as kids. Why would an entire town ignore such horrors for so long? You'll have to watch the movie.

Those kids comprise the Losers Club, seven children who must band together to confront a demonic force that often appears as a clown bearing red balloons. But it's not just the clown that terrorizes. Human beings can be just as menacing in Derry, like the bully Henry Bowers and his gang, who do battle with the Losers multiple times.

We also get a better idea of when the movie takes place. The book, released in 1986, told parallel stories occurring in 1958, when the kids are all 12 or 13 years old, and 1985, when they're adults.

This film tells only the first part, and it looks like it pushes that forward a few decades. The cars and clothes here look '80s style, which would make sense if the sequel (already confirmed) takes place during or near the present day and they're keeping a similar time gap between stories.

IT hits theaters September 8, which can't come soon enough -- except for real clowns, who aren't nearly as happy about all this.

From the studio:

New Line Cinema’s horror thriller IT, directed by Andrés Muschietti (“Mama”), is based on the hugely popular Stephen King novel of the same name, which has been terrifying readers for decades.

When children begin to disappear in the town of Derry, Maine, a group of young kids are faced with their biggest fears when they square off against an evil clown named Pennywise, whose history of murder and violence dates back for centuries.

IT stars Bill Skarsgård (“Allegiant,” TV’s “Hemlock Grove”) as the story’s central villain, Pennywise. An ensemble of young actors also star in the film, including Jaeden Lieberher (“Midnight Special”), Jeremy Ray Taylor (“Alvin and the Chipmunks: The Road Chip”), Sophia Lillis (“37”), Finn Wolfhard (TV’s “Stranger Things”), Wyatt Oleff (“Guardians of the Galaxy”), Chosen Jacobs (upcoming “Cops and Robbers”), Jack Dylan Grazer (“Tales of Halloween”) and Nicholas Hamilton (“Captain Fantastic”).