The film was set in modern - day Los Angeles during a global alien invasion .
The film was followed a platoon of U.S. Marines who are joined by an Air Force special operations sergeant and some Army infantry soldiers in combat operations against the alien enemy .
The film was set in modern - day Los Angeles during a global alien invasion , and followed a platoon of U.S. Marines who are joined by an Air Force special operations sergeant and some Army infantry soldiers in combat operations against the alien enemy .