Lisa and her fiancee John take a weekend trip to a quaint little town for some fun and relaxation. They decide to go on a strenuous cave tour, Lisa the only woman in the group. While many of the others don't think she can handle something so physically demanding, Lisa is determined to prove she can keep up with the guys.

What she doesn't count on is a creature hiding inside the cave, picking off members of her group one-by-one. Forced into being the strongest of the group when all hell breaks loose, Lisa finds courage and strength buried deep inside that she never knew existed in order to battle the beast and save as many of her group as she can.