While hiking in an isolated forest, survivalist Danny Coile (Les Stroud) and old Army buddy Arron James (Stacy Brown Jr.) become hopelessly trapped when they fall into a deep dark cenote with steep walls and no way out. Over the next 85 five days, they transform from mild-mannered old friends into vicious, bloodthirsty animals willing to do whatever it takes to survive.

John Peterson lives with his partner Eric and their adopted daughter in Southern California. When he is visited by his aging father Willis from Los Angeles who is searching for a place to retire, their two very different worlds collide.