Thousands of years ago, a meteor crashes into a remote woodland, bringing with it an unknown creature that survives the impact and hides itself in the depths of a cave system. Fast forward to 1976, James Wheeler enters a cave determined to uncover the truth - and is never seen again. All that's found is a single frame of Super 8 film, capturing the silhouette of a creature. In the present day, Wheeler's granddaughter, Olivia along with five explorers, sets out to investigate the legend of the "Bone Keeper." But as they venture deeper, they realize they are being hunted and the line between hunter and prey begins to blur. Will they uncover the truth and escape the creature - or become the next victims of the Bone Keeper.