Avatar director James Cameron has been hit with a lawsuit by a writer who claims that the plot for the hit sci-fi movie was lifted from his own project.

In the suit, which was filed in Los Angeles Superior Court Thursday, Eric Ryder claims that he entered into an agreement with Cameron's production company, Lightstorm Entertainment, to develop a movie based on his story KRZ 2068.

Read the full lawsuit here.

According to the suit, the project was envisioned as an environmentally themed 3-D epic about a corporation's colonization and plundering of a distant moon's lush and wondrous natural setting.

Also read: James Cameron: Yes, Avatar Is Political

After working on the project for nearly two years, Ryder alleges, Lightstorm put the kibosh on it, explaining that no one would be interested in an environmentally themed science fiction feature film.

Shortly after, the suit says, Lightstorm began work on Avatar, which Ryder says, liberally and substantially uses material that fell within the LEI-Ryder agreement.

According to the suit, Ryder's story involved a protagonist who's sent to the moon of a distant planet by an Earth-based mining corporation; moreover, the details of the project called for 3-D effects to infuse the story.

And since, according to the suit, Ryder's agreement with Lightstorm stipulated that material from the project wouldn't be used without Ryder sharing in the commercial receipts and the writer or producer credits, he wants to get paid from the mega-successful Avatar.

Ryder claims that he was told that Cameron alone wrote Avatar, and that he had prepared a scriptment for the project before Ryder and Lightstorm entered the agreement. Ryder says that's untrue -- and says that his story was circulated to the bigwigs at Lightstorm, including Cameron.

Claiming breach of implied contract, fraud and deceit, negligent misrepresentation and other infractions, Ryder is seeking unspecified contract damages, tort damages, punitive damages and that he be awarded the profits that defendants obtained from their wrongful acts.

Given the billions of dollars that Avatar pulled in worldwide, that could be pretty substantial.

Cameron's attorney and Lightstorm did not immediately respond to TheWrap's request for comment.

Pamela Chelin contributed to this report.

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