Two years after a devastating alien invasion, George Herbert (C. Thomas Howell), a scientist working for the U.S. Army, discovers that the extraterrestrials are planning to attack the planet again, this time by constructing a space-time hole between Earth and Mars. But Herbert is distracted when the Martians abduct his son. As the nations of the world come together to conduct a mission to Mars and defend their planet from another invasion, Herbert fights to get his child back.