Fourteen-year-old Joe Miller thought Bannerman's Island was just an urban legend-a creepy abandoned castle to scare tourists. But when he and his cousin sneak onto the forbidden island on Halloween night, they discover the legends are real. Three spirits have guarded this place for centuries, holding back something dark that's trying to cross over. As paranormal activity escalates, Joe realizes he's witnessed a threat to everyone along the Hudson River. The question isn't whether the darkness will break through. It's when.