Skydiver Fathom Harvill (Raquel Welch) is in Europe with the U.S. skydiving team when a Scottish colonel working for a top-secret western agency approaches her about helping him find a very important atomic device that has been lost. He wants her to use her skydiving skills to parachute into a house to retrieve the device. The house is occupied by some Red Chinese, and on top of all this, there is a Continental doctor who is up to no good. Soon nothing is as it appears and Fathom must discover the truth on her own.