I can remember seeing four monster movies on the 4 O'Clock movie on Channel 30: Destroy All Monsters, King Kong vs Godzilla, Godzilla vs the Smog Monster, and Gamera vs Guiron.
Like a lot of science fiction films, this starts with science, explaining the vastness of space, and touching on radio astronomy, on which the plot hinges. Out protagonists are an annoying kid, Aki, and his Anglo friend, Tom, who are amateur astronomers. They turn out to be the only people watching the sky when the flying saucer lands.
This is the first alien invasion film that acknowledges a language barrier. Tomoko, Aki and Tom's tagalong little sister, asks if the aliens will even understand Japanese. The subject is picked up with the tralslation machine the aliens use. It's a small nod to the increasing sophistication of the audience, or possibly to Star Trek's Universal Translator. It also allows the aliens to converse privately in earshot of the boys by moving their translation devices.
The kids manage to launch the space ship, or perhaps have the spectacular bad timing to be playing at launch when the spaceship decides to head home. When they're threatened by meteors, Gamera shows up to make sure they get through safely. Luckily, these are the only kids on Earth who need help. Gamera then tries to follow the UFO, but it rapidly outpaces him.
Tomoko tries to tell her mother that Aki and Tom have been abducted by a spaceship, but, as an adult in a kid-oriented film, she doesn't believe the kids. Or perhaps she just can't believe she's landed in such a ridiculous plot.
The planet they boys land on is barren and windy, sort of a predecessor of Aliens LV-426, and like Planet X in Invasion of Astro-Monster. It sits on the opposite side of the Sun, a conceit used in another 1969 film, Doppelgänger. Although it was a technologically advanced civilization, they kept churning out monsters until just about everything was destroyed. Computer error, you understand. So Space-Gyaos, like Earth Gyaos, but silver, is rampaging. The ground opens up, revealing Guiron, who's got a massive knife blade for a head. Guiron is likely the inspiration behind Knifehead, in Pacific Rim. Like many of Gamera's opponents, and Yonggary, it has projecting lower tusks.
What follows is a pretty clinical dissection of Gyaos. Guiron reflects Gyaos's sonic beam back, severing its leg. Then it leaps into the air, cutting Gyaos's wing off. On the ground and helpless, Gyaos then loses its other wing, and then its head. I can't help thinking that Guiron's head blade is about as sharp as Gypsy Danger's sword. No blood and guts, though. Just some purple flesh where Guiron cuts. This sets Guiron up to be pretty tough, since Gamera didn't have an easy time defeating the non-space Gyaos.
Guiron, it turns out, is the watchdog for the last tywo remaining Terans, Barbella and Flobella. Like the Kilaaks from Destroy All Monsters, they control their monster. Why they can't control the Gyaos with the same technology is left unexplained. It's oddly like Katsura controlling Titanosaurus, silver spandex and all, from Terror of Mechagodzilla. And their space-spandex fits them quite well. The Teran civilization has a lot of technology, but the errors in the system has somehow created the Gyaos monsters, which destroyed the civilization. Like the Viras aliens, they also have a mind probe. And it provides us with an opportunity to show stock footage of Gamera's past exploits, but only three minutes' worth this time. We get brief moments from all the previous films except Barugon, for some reason. Perhaps because it doesn't have any moments that demonstrate Gamera's ongoing friendship to children.
These aliens are pretty, but they've got their horrific side. While the kids are sleeping, the Terans decide to eat their brains, raw, to absorb their memories. Aki's head gets shaved with a razor stuck into a plastic ray-gun toy. It's a creepy moment, and Aki goes through the rest of the film with very short hair. This is more menace than a lot of kids' films offer, and gives it just enough edge to make it palatable to me as an adult.
Just as they're about to cut into his skull, the red alert sounds, letting them know Gamera has landed. And then there's nothing for it but Guiron has to fight Gamera. As is standard for these films, Guiron wins the first round, and Gamera retreats. In the meantime, the boys escape and engage hijinks, causing Guiron to attack the spaceship the Terans are escaping on, a plot point used later in Godzilla vs King Ghidorah. After this, Guiron attacks the structure where the kids are, but Gamera comes to their rescue.
Gamera jams half a missile into Guiron's head, then breathes fire on it, detonating it.
The rest of the film is the usual reconciliation with Mom, getting back to Earth stuff. The science folks who greet the kids after they get home are much more interested in what they've learned than the fact that they're the only humans to have been to another planet. Or that Aki's had his head shaved and looks suspiciously like a newly-inducted cult member.
Gamera vs Guiron is one of the better Gamera films. The plot holds together better than most of the prevoius ones, and the doses of actual threat keep the film from being dull. One annoying piece is that the writer repeats his two conditions for a more advanced civilization four times, with exactly the same phrase. Tera has no wars and no traffic accidents. It's a strange pair of points, although I understand that the Vietnam War was in full swing when the film was made. And increased urbanization led to more traffic accidents. But really, what the hell?
Next up, Toho skips making a Godzilla film in 1970, so we'll go straight to Gamera vs Jiger.