After Earth is a 2013 American science fiction action adventure film directed by M. Night Shyamalan, which he co-wrote with Gary Whitta, based on an original story idea by Will Smith. In the future, an environmental cataclysm forces the human race to abandon Earth and settle on a new world, Nova Prime. One thousand years later, the United Ranger Corps, a peacekeeping military commanded by General Cypher Raige, comes into conflict with alien creatures who intend to conquer Nova Prime. Their primary weapons are the Ursas: large, blind predatory multi-limbed creatures that hunt by sensing pheromones the human body secretes when scared (they literally smell fear). The Rangers struggle against the Ursas until the impassive Cypher learns how to completely suppress his fear, in effect becoming invisible to the Ursa—a technique called "ghosting."