In an effort to find an economic means of purifying salt water, a joint U.S.-Japanese military command is set up on an isolated Japanese island where an unusual salt water lake is situated. However, their purifying experiments arouse the prehistoric monster Obaki from hibernation at the lake's bottom, and it proceeds to attack Japan. Although made by a U.S. independent film company, this film was based on a Japanese Toho monster film of 1958, "Daikaiju Varan", from which all of the monster effects scenes and a few incidental dramatic shots were edited into it.

In 1976, a drifting star named Gorath is discovered to be on a collision course with Earth. Although it is smaller than Earth, its enormous mass is enough to destroy the planet totally. A mission sent to observe Gorath is destroyed after the ship is drawn into the star, with a later mission barely escaping the same fate. However, Astronaut Tatsuma Kanai is left in a catatonic state due to his near death experience. Unable to destroy the invading star, Earth's scientists undertake a desperate plan to build giant rockets at the South Pole to move the planet out of Gorath's path before it is too late.

When a rare species of butterfly is found in a mysterious valley in Japan, a pair of entomologists go to investigate and find more. They discover Varan, a giant monster, who decides to leave the valley and head straight for Tokyo.

Three competing parties all race against time to track down an elusive creature known only as the Snowman.

Admiral Isoroku Yamamoto, a brilliant tactician, is a loyal subject of the emperor, despite his grave misgivings about leading Japan's navy into war with the United States. He opposes the attack on Pearl Harbor, but, overruled, he leads his forces to the best of his ability.

After graduating from a high school in the Seto Inland Sea, Koji, a childhood friend of Yaeko, went to Tokyo to enter university wearing a heartfelt sweater.