Scientist Dr. Russell Marvin (Hugh Marlowe) and his new bride Carol (Joan Taylor) are driving to work when a flying saucer appears overhead. Without proof of the encounter, other than a tape recording of the ship's sound, Dr. Marvin is hesitant to notify his superiors. He is in charge of Project Skyhook, an American space program that has already launched 10 research satellites into orbit. General Hanley (Morris Ankrum), Carol's father, informs Marvin that many of the satellites have since fallen back to Earth. Marvin admits that he has lost contact with all of them and privately suspects alien involvement. The Marvins then witness the 11th falling from the sky shortly after launch.
When a saucer lands at Skyhook the next day, soldiers open fire, killing one exposed alien, while others and the saucer itself are being protected by a force field. The aliens then kill everyone at the facility but the Marvins; General Hanley is captured and taken away in the saucer. Now too late, Russell discovers and decodes a message on his tape recording from the aliens: they wanted to meet with Dr. Marvin and had landed in peace at Skyhook for that purpose. Now impatient to conduct that meeting because everything has gone sideways, Marvin contacts the aliens and steals away to meet them, followed closely by Carol and Major Huglin (Donald Curtis). They and a pursuing motorcycle cop are taken aboard a saucer, where they learn that the aliens have extracted knowledge directly from the General's brain; he is now under their control. They claim to be the last of their species and have destroyed all the launched satellites, fearing them as weapons. As proof of their power, the aliens then give Dr. Marvin the coordinates of a naval destroyer that opened fire on them, and which they have since destroyed; the Marvins are then released with the message that the aliens want to meet the world's leaders in 56 days in Washington, D.C., to negotiate an alien occupation.
Dr. Marvin's later observations uncover the fact that the aliens' protective suits are made of solidified electricity, and grant them advanced auditory perception. From other observations, Marvin develops a counter-weapon against their flying saucers, which he then later successfully tests against a single saucer. As they escape, the aliens jettison Gen. Hanley and the motor cycle cop; both fall to their deaths. Groups of alien saucers then attack Washington, Paris, London, and Moscow, but are destroyed by Dr. Marvin's sonic weapon. The defenders also discover that the aliens can be easily killed by simple small arms gunfire once they are outside the force fields of their saucers.
With the alien threat eliminated, Dr. Marvin and Carol quietly celebrate the victory by going back to their favorite beach, resuming their lives as newlyweds.
How do the alien saucers provide protection for the aliens?
force fields