A lot of godzilla fan anime ideas are about the big G himself, but what about all those people in tanks, fighter planes, maser/mazer tanks, mechas and tanks? well this is their story. The universe the story takes place in is a mixture of Heisei, 2014 and tokyo sos verse, with bits of showa and final wars thrown in.
The earth has mostly given up war between nations (war still happens though) as they have now put most of their efforts into fighting Kaiju, the leading organization in this fight is G-force, which was created in 1955, a year after Godzilla first destroyed Tokyo to combat the creature. They also fought the other Kaiju during the king of the monster's occasional absences. During 1999, after years of fighting, Godzilla was once again frozen in a block of ice, either floating on, or at the bottom of the western side of the bering sea thanks to Kiryu, Mothra and the Gotengo which would seem to make things easier. Unfortunately for G-force and their rival/partner group the AMF this led to the rather Knight Templaresque CrisisControlIntelligence or CCI becoming a powerful force in Japan and the world.