Andrew is haunted by the nightmare of dying a horrible death in the claw of a rampaging creature. A friend convinces him the only way to conquer imagined fear is to confront it head on. When they invite an adventurous group of off-roaders for radical cycling in remote terrain, no one knows they are being led to the time and place the nightmare unfolds. As sunset plunges them into darkness, the dreadful dream turns real, and they are attacked by the Catcher, a skilled and brutal collector of human specimens for alien science. They are no match for the deft hunter, and it picks its victims, dragging them into an underground catacomb. When Andrew's girlfriend is seized, he confronts the ultimate terror by tracking her into the unknown danger below. In a courageous rescue, they attempt escape, but the vicious visitor has marked them with a scent, and it pursues in an unrelenting attack.