Atomic scientist/pilot Doug Martin is missing after his plane crashes on an reconnaissance mission after a nuclear test. Miraculously appearing unhurt at the base later, he is given sodium amethol, but authorities are skeptical of his story that he was captured by aliens determined to conquer the Earth with giant monsters and insects. Martin vows to use existing technology to destroy them.
A botanical expedition to the Himalayas captures a Yeti and brings it back alive to Los Angeles, where it escapes and runs amok, seeking food.
When a scheming fortune hunter finds his rich wife is not going to die as expected, he and his lover make other plans to get her millions.
