Ross and Matt Duffer, who are the brothers behind the popular Netflix series Stranger Things are being sued by someone who believes that the two stole his idea.

Charlie Kessler says that he met the pair back in 2014, at the Tribeca Film Festival, and that he described to them concepts for a short film entitled Montauk, and that he also talked to them about his plans to develop a feature film based on it, called The Mantauk Project.

On Tuesday, Kessler filed a lawsuit at the Los Angeles County Superior Court. The suit claims that the Duffer brothers — after having had discussions with him — stole his intellectual property and then used it to create Stranger Things, which began airing in 2016. The suit further insists that the two brothers had explicitly agreed not to disclose Kessler’s idea or exploit it.

The lawsuit lists many similarities between Stranger Things and Kessler’s projects. For example, Stranger Things was originally entitled “Montauk” before it was produced. The suit cites many examples of where this title was used in news articles prior to the launch of the show. It also cites similarities in the plots of both projects, including the towns where they take place.

Kessler is not only seeking restitution from the Duffers, but he also wants to destroy all materials that have been made based on his property.

Alex Kohner, who is a lawyer representing the brothers, says that the two have never seen Kessler’s short film or have ever discussed it or any other project with Kessler. He further said that this was just an attempt by Kessler to exploit the Duffer Brother’s success.

So far, Netflix has yet to comment on the suit.