After some introductory narration, we open on a bogus-looking backdrop, representing a house in a peaceful suburban neighborhood. That night, young David McLean (Jimmy Hunt) sees a spaceship crash into a nearby sandpit. His father (Leif Erickson) goes to investigate, but comes back changed. Where once he was cheerful and affectionate, he’s now sullen and snarlingly rude. Others fall into the sandpit (accompanied by the sound of a heavenly choir—an effect that works better than you’d think) and begin acting like him: cold, ill-tempered and conspiratorial. David knows that aliens are taking over the bodies of humans, but he’ll soon discover there have been far more of these terrible thefts than he could have imagined.

Unlike his successor in “The Invasion of the Body Snatchers,” this young doom-monger finds some serious help in a lady doctor (Helena Carter, in an appealing performance) and a brilliant astronomer (Arthur Franz). Here the script becomes too talky; but later the doctor and the boy fall into the sandpit themselves, and we enter the bubble-filled interior of the spaceship. There we meet mutants (pronounced, for some reason, as “Mute Ants”), who are green aliens with insect-like eyes. These ludicrous beings prove to be slaves to their leader: a large, silent head with ceaselessly shifting eyes and two tentacles on either side, each of which branches off into three smaller tentacles.

This is a movie tailored to a perfect fit for any little boy, made as it is with space ships, green men, tanks, soldiers, ray guns, exploding buildings, exploding people, and even a sinister little girl coming to a fatal end. The young hero is intelligent and resourceful and is taken seriously by everyone, even—or especially—the people-cum-evil-aliens who try to denounce him as a little crackpot. Bobby Driscoll’s character in “The Window” should have had it so good.

William Cameron Menzies directs, doing what he can with a severely tight budget. The stylized sets look pretty good; but the green-carpet costumes for the alien slaves are awful, especially their zippers. The opening scenes showing the boy’s happy family life are phony and awkward. Otherwise, the first half hour is the best, as it usually is in monster movies. Waiting for aliens is more fun than seeing them.

The fun ends just before the movie does: whoever decided on the it’s-all-a-dream cop-out must have had an alien device stuck in the back of his neck