When a scientific experiment to spawn giant-sized ants goes awry, the bloodthirsty insects get loose and wreak havoc on the city. At first, it seems the only safe haven is a towering skyscraper in the center of town, where a group of terrified survivors (including C. Thomas Howell) have locked themselves away. But soon enough, the ants figure out how to access the building, and staying alive becomes the only way out.