Earth vs. the Flying Saucers

Dr. Russell A. Marvin and his wife, Carol, encounter a flying saucer while driving to a military base, where they accidentally record a message on their tape recorder. When they arrive, they learn that the first ten rockets in Operation Sky Hook mysteriously fell back to Earth. The aliens, whom Dr. Russell decodes the message to communicate with, demand a meeting with Earth's leaders in 56 days to discuss an invasion, and Dr. Russell must develop an anti-magnetic weapon to save humanity.