Body Snatchers

After Environmental Protection Agency inspector Steve Malone travels to a remote army base so as to look after toxic substances, he also brings his family together for the ride. After arriving at the bottom, his teenaged daughter Marti befriends Jean Platt, daughter of the foundation’s commander, General Platt. When people in the bottom start acting strangely, Marti becomes convinced they are gradually being replaced with plant-like aliens.