Things open with a black-and-white flashback to the orginal "Gamera" ("All scale models were powerless against him."), and then we're informed that the rocket shooting the giant turtle off to Mars collided with a big red meteoroid en route. Gamera spins back to Earth, blue flames shooting from where he's pulled his arms and legs into his shell ("Looks like a big chicken pot pie."), and once back smashes through a hydroelectric dam to obtain energy. Untroubled by this alarming turn of events, a crippled Second World War veteran enlists his brother and two other people to go to New Guinea and recover a huge opal he found during the fighting. Landing in a village and ignoring the warnings of a comely villager and a Japanese doctor staying to help out, they locate the opal in a cave. One searcher gets a little over-excited about this, and misses the scorpion clinging to his leg for a considerable length of time until he's stung at last. ("He died as he lived: goofy.") One of the remaining searchers double-crosses the brother by by lighting the long fuses on the grenades they took with them, but the brother is rescued and prepares to return to Japan with the attractive young villager.
In the meantime, the opal turns out to be an egg, which gooily cracks open ("Caution, filling is hot.. and alive.") and sinks the double-crosser's boat just as it gets to Japan. Now grown to full size, the monster Barugon lumbers ashore, ("Hi. I'm a juicy new character. Enjoy me! I'm what's known as the antagonist.") a sort of big lizard with a horn on the snout, moving on all fours and looking a bit more like someone crawling on his hands and knees in certain shots. Barugon is equipped with a somewhat disturbing tongue that shoots out like a rigid, meaty Q-tip, and if that can't reach something it can spray freezing vapour. ("Frosted mini tanks, gang!") For extra-long range attacks, Barugon can generate a deadly rainbow from the sawtooth spines on his back.
The brother and the villager make it back to Japan, only to find that the veteran has been killed in the carnage after the double-crosser got into a brawl with him and tipped a locker down onto him. ("Oh great, finish him off with a bowling locker.") A variety of super-scientific plans are deployed against Barugon, including attempting to reflect his deadly rainbow back at him using a mirrored radio telescope and luring him into a lake using a huge diamond provided by the villager and then specially treated. All of it of course fails miserably, although the double-crosser does manage to grab the diamond from its special apparatus whereupon he's at last snared by Barugon's tongue and devoured. All of it may perhaps, though, have delayed Barugon long enough for Gamera to thaw out after an initial attempt to attack him for his energy ("Finally, a fight."), and also moving more or less on all fours ("If you think of this as two guys in rubber suits, it's really sad."), Gamera conclusively defeats Barugon and flies away, his earlier attack on the dam either forgiven or forgotten.
The "host segments" of this episode are also fun. They open with Tom Servo trying to work a PC (although his hands, hidden behind the CPU, seem to be typing just fine) as a bored Crow reads "Byte" magazine, and then, frustrated, launching into a "user interface war." The official episode guide informs us that those used to rage among the writers until "Doom came out and settled the issue"; considering that unfair, I would always wish that the Macintosh users could have "held out for Marathon." In any case, the argument harkens back to a time when there still seemed to be a genuine philosophical divide, before the "graphic paradigm" was adopted by the opposing side and the debate effortlessly shifted to "sticker price" versus "fit and polish," and Joel tries to defuse the whole issue with soothing words to the audience and also mentions the Commodore Amiga as the last part of the joke. For years to come, MSTings (with their greater awareness of computing) would have Tom the Mac user and Crow the PC user, although one late work by a new "MSTer" had Crow the Mac user and Tom the PC user. I informed the author of this if with just a little tickled amusement, and later collaborated with him in a big "group MSTing." The next host segment is more universal, featuring Tom Servo reading at high speed the advertising copy for the "5,000 piece fighting men 'n' monster set" as still images of a pretty impressive display of plastic soldiers are displayed.