Japan and the rest of the world are again in grave danger after an evil amoeba-like alien emerges from a spaceship crash and turns an octopus, a crab, and a turtle into gigantic city-squishing terrors. An entrepreneur sees the creatures not as destructive forces to be destroyed, but as a gold mine with the potential to bring in millions of bucks from curious tourists. Alas, as with all promoters of gigantic creatures, he soon finds himself at their mercy.