Adapted by John Mantley from his own novel, The 27th Day is an ideas-driven sci-fi thriller conceived and executed by idiots. What's interesting is how close its plot comes to the genuinely intelligent Arrival. One could imagine Arrival being back-engineered by taking The 27th Day and reversing all its stupidities.
Things start off with promise: five disparate stereotypes (American newspaperman, English girl in swimsuit, Chinese woman, German scientist, Russian soldier) are snatched from their lives by a UFO. But already there are problems apparent: the movie doesn't give any of these characters a compelling narrative to be interrupted by the main plot, except the Chinese woman, whose narrative is ending, as we'll see. In the novel, perhaps access to the characters' thoughts would have enlivened them, and this may be one reason authors don't usually get invited to adapt their books: faithfully reproducing the incidents onscreen doesn't necessarily give you the same effect. (But Mantley was an experienced TV writer and producer—Gunsmoke and later Buck Rogers—he ought to have known.)
On the alien craft (a traditional saucer design) we meet Arnold Moss—a fun actor when he felt like it, here constrained by his role, which he plays like he's auditioning for a biblical epic, slow, anglicized and dripping with dopey, portentous authority, while standing with his feet planted far apart as if he's uncomfortable in his space pants.
"Perhaps it would be simplest to call me... The Alien," says the lugubrious extraterrestrial, to inadvertent hilarious effect (but not on the other characters, who, true to genre convention, evince no sense of humor at all). The Alien then lays out the needlessly complicated and obscure plot: he's giving each of the five a sort of perspex powder compact containing three deadly capsules. Each of the five can trigger their capsules using the power of their mind, and cause them to strike at the latitude and longitude of their choice. The total effect of all the capsules being triggered will destroy all human life (animals, plants and real estate being unharmed).
(It's good that all this exposition is handed to the velvet-voiced Moss, even though his characterization is hokey and dumb, because he's a pleasure to listen to in purely aesthetic terms.)
We then get an elaborate description of the radius of destruction of each capsule: Moss at first says each capsule can cover three thousand square miles. Even multiplied by fifteen, that seems to fall rather short of the necessary trillions. (Science-fictioneers often seem to not understand about planets being big, even their own. Note how in Star Wars films you can always find the person you're looking for by touching down at random and then walking.) But not to worry: the figures Moss cites will then be contradicted every time the subject comes up, until finally just six capsules can be used to blanket the Earth.
Also, the Alien says he's from another universe, whose sun is dying. To hell with that guy. To hell with this film.
But there's an hour to go yet. The Alien's motivation is that he would like to depopulate the Earth so his people can move in, what with their sun dying and all. But his moral code prevents his people attacking us directly, so he's simply giving us the means to effect our own annihilation, fairly confident, based on our track record, that we'll use it within the 27 days that the capsules remain potent.
The humans are returned whence they came, and the Chinese woman immediately commits seppuku (I know, right?) in front of a Buddha, and the Brit lady throws her capsules in the sea.
Then the sneaky Alien immediately doxxes his former abductees on national television, forcing them all to go on the lam.
The Russian soldier is captured and interrogated by his Kremlin superiors, who are determined to gain control of this new weapon. The American and Brit meet and hide out in a shack by a race track in the lamest version of It Happened One Night's "walls of Jericho" scene you ever saw. They spend ten of the days dynamically doing nothing. The German scientist (George Voskovec, the eleventh-angriest of the Twelve Angry Men) wanders in front of a (slowly) speeding car, and there's an interesting possibility that his subsequent concussion might result in him nearly launching his capsules by accident—but this idea occurs to us and apparently not to the filmmakers.
The three Westerners eventually go to the U.S. authorities, who prove to be uniformly wise and decent, thus eviscerating another possible source of drama. A test is conducted on a patch of ocean, with one fatally ill test subject in a dinghy with a goat (to see if the destructive potential is really limited to humans). A fatally ill man being disintegrated in a dinghy with a goat would seem like the very definition of bathos—and it is.
It is frankly unbelievable where all this is headed. I warn you.
Anyhow, the German scientist discovers lettering on his capsules. He needs to look at the other capsules to read the message. The Russians apparently never looked at their capsules too closely. And the message is complete if you just look at the Western ones. You see what I mean, about reversing all the dumb stuff in order to get Arrival?
George Voskovec reads the message and then launches his capsules, blanketing the Earth: because the capsules will only kill enemies of freedom! So the dinghy goat man was an enemy of freedom? He seemed so nice. So, from starting off with a Day the Earth Stood Still type anti-war message, the film ends up celebrating the deaths of maybe millions of people. Kill all the bad guys and everything will be fun.
And at last a truly united United Nations sends a message to the Alien inviting his people to come and stay. Because despite his plotting to get us all killed, he's obviously a terrific chap when you know him.
The End... or The Beginning? No, it had best be The End, I think.