Professor Madeleine Abbot is called in to investigate a series of mysterious disappearances in Kelley Swamp. When the disappearances are linked to a series of attacks by flying saucers, Professor Abbot hitches a ride aboard the Navy dirigible Peregrine to chase the saucers to a space-time portal above the Pacific Ocean.
In 1952, a secret Air Force spy balloon is mistaken for a flying saucer. The balloon project’s security chief thinks the young writer who broke the story must be a communist agent — but the writer is convinced that the security guy is an alien sent to silence him! It’s up to the Air Force’s chief flying saucer investigator to sort out the mess before the writer gets arrested for espionage.