In the summer of 1945, war is reigning in the Pacific Rim while Syms Thorley continues his life as a B-movie actor. But the Navy would like to use Thorley in their top-secret Knickerbocker Project, putting the finishing touches on the ultimate biological weapon: a breed of gigantic, fire-breathing, mutant iguanas. Thorley must don a rubber suit that will transform him into the merciless Gorgantis, and star in a film that simulates the destruction of a miniature Japan. If the demonstration succeeds, the Japanese will surrender, sparing thousands of lives; if it fails, the mutant lizards will be unleashed.