Maneater centers around the famous Algonquian myth of the Wendigo, an evil, cannibalistic spirit. Humans can either transform into it by engaging in cannibalism, or be possessed by it via a dream. If one of those unpleasant fates befalls you, you'll go crazy eating your fellow humans, your hunger never to be satisfied. So try not to dream up a wendigo spirit and for heaven's sake, don't eat the flesh of your fellow humans.
The cannibalistic aspect makes it the perfect fodder for a horror movie, and it's been used numerous times, most recently (and probably most notably) in 2001's Wendigo. Now Emanuel is taking on the legend, inspired by a story told to him in the 1970's. His version will follow a former FBI profiler who is now working humbly as a small town sheriff. He begins investigating a series of mysterious (and probably gruesome) murders, only to discover that the monster he's hunting may be someone he knows very well.
It sounds like the best X-Files episode never written, doesn't it? Or at least a really good issue of Wolverine. I think Emanuel needs to delay production, and offer it to Chris Carter or Marvel Studios. Both are in need of a good cannibal spirit story, don't you think?