Stranger Things has been one of Netflix's biggest success stories, but now a lawsuit claims that creators Matt and Ross Duffer stole the idea from someone they worked with in the past.

Director Charlie Kessler recently filed a lawsuit against the brothers, alleging that he pitched them on an idea for a project that takes place on Long Island, New York near an abandoned military base and has sci-fi elements including government experiments. This was apparently a feature-length version of Kessler's short film Montauk called The Montauk Project.

He reportedly spoke with the Duffer brothers about this during a party at the Tribeca Film Festival in 2014. At this party, Kessler said he discussed "the script, ideas, [and] story" for the project, and it was his understanding that there was an "implied contract."

In 2015, the Duffer brothers sold Stranger Things to Netflix, and in fact used the title Montauk when doing so. Stranger Things was originally set in Montauk, Long Island before changing to Indiana.

According to the lawsuit (via EW), Kessler's original idea for Montauk included a number of elements that later showed up in Stranger Things. Among these are a young boy who vanishes mysteriously, a government conspiracy about experiments on children, and a police officer wrecked by his past seeking to find the child. Kessler's outline also included a monster that can movie through portals to other dimensions.

According to Spin, Kessler's attorney, Michael Kernan, said the Duffer brothers have made "huge sums of money by producing [Stranger Things] based on [Kessler's] concepts." The legal team for the Duffer brothers said the lawsuit is "completely meritless."

"The Duffer Brothers have neither seen Mr. Kessler's short film nor discussed any project with him. This is just an attempt to profit from other people's creativity and hard work," lawyer Alex Kohner said.

Kessler is seeking for punitive damages and lost profits, and he also wants the Duffer brothers to destroy "all materials of every nature and kind in their possession" relating to the project. You can see the full lawsuit below.

Kessler v Duffer by ashley6cullins on Scribd

Stranger Things 3 was confirmed in December. Netflix renewed the series on the heels of Stranger Things 2's debut just before Halloween, when it was watched by a third of the the streamer's US subscribers. Although it currently has no confirmed release date, star David Harbour told Variety in December that fans "probably won't get it until sometime in 2019." In the meantime, click here to see GameSpot's theories about Season 3.