An American sailor (Buster Keaton) is shipwrecked at the end of World War II, and as he drifts on the Pacific awaiting rescue he is delighted to see a plane overhead drop a lifeboat for him to replace his tiny dinghy, though not so much when it means he's still drifting, only in a bigger vessel. Eventually he sights land, and goes ashore thinking he is in Japan, not knowing they have recently surrendered, but he is in fact in Mexico and on arriving in the nearest town he offers himself to the people there as a prisoner of war. Not sure of what to do with him, they comply with his wishes and take him to jail...
Boom in the Moon, or El moderno Barba Azul as it was known in its native Mexico, is a film which it's safe to say suffers a very poor reputation, though a lot of that was to do with how far its star had fallen from his heyday in silent movies where he was one of the most popular comedians around after Charlie Chaplin and Harold Lloyd. Those two gentlemen had invested their money wisely, and still had control of their work when their popularity began to wane, but Keaton had basically given it all away, and many's the fan who would lament his decline once the talkies arrived, though paradoxically his movies of the thirties were more popular with the public at the time than his twenties achievements had been.
Some would say his classic The General was the beginning of that fall from grace, not because it was particularly terrible, but because it was a flop, so from then on producers tended to trust him less and less to guide his own movies, leaving him adrift for the rest of his career, taking the work where he could find it. Which brings us to this, which saw producer Alexander Salkind coax him to Mexico to make something which has generated little love down the years, though Keaton himself, now entering his fifties, must have been happy to be starring in a film again, even if it would be the final feature where his name would be above the title. There were bits of business throughout which indicated he was given a free hand to add as many gags as he wanted, too.
Which meant plenty of physical comedy at odds with the sillier plotline he was saddled with, which took the form of science fiction which wasn't really: there was a space rocket in it set on course for the Moon, but the manner in which nobody actually got there scuppered any hope for something more imaginative, though oddly this premise was utilised for the first half of Abbott and Costello Go To Mars some ten years or so later. Here Buster was mistaken for the serial killer Bluebeard (the Mexican title meant The Modern Bluebeard), so the joke was this harmless fellow underwent all sorts of indignities because the other characters were not too bothered if he went to be executed or went to the Moon as a guinea pig or... or anything much else.
Buster, whose character is never named, acts as if he only had the vaguest grasp of what was going on anyway, not speaking the language which if you see the dubbed into English version is not so clear since everyone is speaking English in that, handicapping one of the main running jokes. He does wind up in the cell with a ne'erdowell (Ángel Garasa) who becomes the straight man to Keaton's antics, and when a local professor recruits them both for his lunar experiment (he's unable to choose between them when they both claim to be Bluebeard) they each board the rocket along with the professor's daughter (Virginia Serret). Needless to say, aside from the star's manful efforts to divine some laughs, none of this is funny, but then you would be comparing it to Keaton's silent favourites and that would be a mistake when he was operating in reduced circumstances. He didn't embarrass himself at least, even if the film around him was embarrassing - and downright strange in places.