A former employee of James Cameron's Lightstorm Entertainment studio has launched a lawsuit claiming he spent two years developing a film which was the basis for Avatar but has not been sufficiently renumerated for his efforts, according to the Hollywood Reporter.

Avatar, which was released in 2009 and made $2.8bn, is both the highest-grossing and most pirated film ever made. It has also been the target of numerous suits alleging plagiarism, though none has yet been successful. Eric Ryder's case rests on work begun in 1999 when as a Lightstorm employee he wrote a story called K.R.Z. 2068, and then created treatments, photos, 3D imagery and character elements for film transfer. It was to be an "environmentally-themed 3D epic about a corporation's colonisation and plundering of a distant moon's lush and wondrous natural setting," Ryder alleges, including "a corporation spy", "anthropomorphic, organically created beings populating that moon", and a romantic attachment which develops between the spy and one of the beings which triggers a revolt against the corporation's mining practices.

In the suit, obtained by the Hollywood Reporter, Ryder says he and Lightstorm had an implied agreement which would lead to credit and compensation for his work. He says that in 2002 Lightstorm said the idea didn't have legs on account of a widespread apathy towards eco-themed sci-fi. Cameron has not yet commented, though Ryder's suit does acknowledge the director says both came up with the concept for Avatar, and began writing, before 1999.