This Island Earth (1955)

Nuclear physicist Cal Meacham begins experiencing strange phenomena. First his plane has a burnout and just before it crashes, it is surrounded by a green glow and lands safely. Next he receives the parts for a strange device called an interroceter. When he assembles the device, it puts him into contact with an individual named Exeter. Exeter, then invites Cal to join a group of scientists on a secret research project. He then boards a remote controlled plane which takes him to a secret location. When he lands he meets old flame, Ruth Adams. They then go to a house where a secret lab is located. After Meacham meets his hosts he begins his work but soon he decides to escape with Ruth and fellow scientist Steve Carlson. During the escape attempt, Carlson is killed as well as several other scientists that were at the house. Cal and Ruth eventually discover that Exeter is an alien from the planet Metaluna and the reason they were kidnapped is to help Exeter and his people find a new source of energy to aid in their war with the warlike people of the planet Zagon. When they arrive on Metaluna, they meet the leader who informs them that the planet is on the verge of collapse and the only viable alternative is to move to Earth.