An adventurous camping trip turns into a blood-fueled frenzy in this adrenalin packed horror extravaganza.When six friends journey into the remote wilderness to study an ancient rock painting at the entrance to a cave, they unwittingly awaken a dormant evil.After one of them goes for a midnight skinny dip in a waterhole, she regresses, bleeding, feverish and confused, into a vicious predatory state - and suddenly her friends are no longer friends, they're food. As she hunts them relentlessly, they too are forced to face their own basest impulses in the increasingly bloody fight to survive - all the while unaware that she's not only eating the dead, but feeding an ancient entity deep within the cave itself...Primal scores big on blood, low on survivors.