When a hike in the woods leads to the disappearance of Lexi's sister, Amara, she recruits her cousin and three friends to help track her down. However, nothing is as it seems in the small town of Hecate, Texas. Strange sounds start coming from the forest, people are going missing, and her aunt keeps muttering about an unknown evil she calls the Hydren. Now, it's up to the teens to find out what really is happening in the woods, but can they kill it before it kills them?