Bright sun, warm waters and sandy beaches beckon countless Americans every year, particularly young adults seeking inexpensive fun. Enter Amy and Stacy, two best friends who bring along their very different boyfriends--focused med student Jeff and free-spirited partier Eric. As the group’s vacation nears its end, they journey into the lush Mexican jungle in hopes of seeing some ancient Mayan ruins. But when they arrive at the magnificent site, an unexpected event drives the frightened travelers to the top of the crumbling stone structure, where they confront hidden deadly horrors and engage in a brutal battle for survival.