After reports of flooded mines, the small town of Kitamatsu is shaken by reports of the death of multiple miners by mysterious circumstances. What was the cause of death? Why are the mines flooding? What is the secret hiding in the heart of the mountain?

Shiochi Tsukioka and Koji Kobayashi, two scout pilots, make a horrifying discovery after Kobayashi gets stranded on an island: There is a second Godzilla! To make matters worse, he's brought along a new monster with him: Anguirus! When news of this revelation makes its way to the mainland, fear grips the nation. With these two titans of terror set on a collision course with Osaka, a counterattack is devised to lure the two creatures away. Will the counterattack be successful? Or will Japan have to face destruction at the hands of Godzilla a second time?