When the huge drift atoll is found in the Pacific Ocean, the mysterious missing persons case occurres in Himegami Island of Kyushu. An ornithologist Mayumi Nagamine hears the “Bird! Bird!” from the radio and never hears again. She visits the island to investigate the island and witnesses the huge shady bird. On the other hand, Yonemori from Japan Coast Guard and Kusanagi from the insurance company decipheres the inscription of the stone monument by the coral reef, turning out to know that the atoll is Gamera and the shady bird is Gyaos and they are ancient monster.