Two pilots are searching for schools of tuna(they work at a tuna cannery), and are forced to land near Iwato island due to a malfunction in one of the planes. While on the island, they see two monsters fighting, one of which they recognize as Godzilla. We later find that the other monster was Anguirus, and that the two monsters are bitter enemies. The two continue to fight, until Godzilla finally destroys Anguirus, throwing him into a moat and burning him to a crisp. Later, the two pilots find out that Godzilla had destroyed one of their fishing boats, and one of them goes and searches for the monster. The other pilot attempts to bomb Godzilla while the first distracts him, but they have no effect, and the first pilot is killed by Godzilla's atomic ray. The remaining pilot noticed that Godzilla could be trapped instead of killed, when he realizes that firing missiles at the nearby mountain would cause an avalanche, and he does just that.
This movie definitely wasn't one of my favorites in the Godzilla saga, but I like it anyways. I give it a six on my rating system because this movie partially layed the groundwork for all following Godzilla movies, and the addition of a new monster was entertaining. It was a very good choice on Tojo's part, because it allowed for more diversity, instead of just having humans fighting Godzilla and on rare occasions defeating him.