The Ruins follows two American couples, just out of college, enjoying a pleasant, lazy beach holiday together in Mexico as, on an impulse, they go off with newfound friends in search of one of their group—the young German, who, in pursuit of a girl, has headed for the remote Mayan ruins, site of a fabled archaeological dig. This is what happens from the moment the searchers—moving into the wild interior—begin to suspect that there is an insidious, horrific “other” among them.