The Algonquin Falls grand opening proves deadly when creatures of myth emerge from below and begin slaughtering every man, woman and child. Trying to avoid being killed and eaten, Jesse and his group have no choice but to enter the expansive cave system under their feet and search for alternate means to escape the state park. Soon they meet up with Charly and her band of survivors that are on a rescue mission, and together they join forces where not only are they outnumbered, but something much larger, more powerful, is also on their trail.
Estranged Ana and Rachel Logan take a much-needed vacation to Thailand - perhaps their sisterhood could even be mended along the way. After an intense party session their group mysteriously wake up on a boat, the ocean carrying them toward a seemingly deserted island. As nightfall hangs over them, tempers rise, survival instincts kick in, and something evil lurks in the wilderness. Who will perish to the unknown?
Kate Woodson's life is not what she expected. Once being a very active and lively woman, she now is a victim of her own body. Happiness is a thing of the past, however Andrew believes they can find some form of it in Maine, where a lake-house becomes available for the summer. The married couple thus set off, eager and full of hope, desiring the serenity of nature. Nature has other plans, however, as something resides within the dark, and it seeks their undivided attention.