Dr Tom Merrinoe (Philip Abbott) is working at the lab one day when he is surprised by a visit from the military: General Swayne (Harold J. Stone) to be exact, and he is looking for answers. After greeting him, Merrinoe takes the General and his aides down nine levels underground to the computer that can give him his answers, a huge mechanical superbrain that is able to solve just about any problem it is faced with. It has been the scientist's pet project for a number of years now, and he believes it is foolproof, so when the inquiries lead to the new, top secret space platform that the United States are planning to launch, the General is not too happy about what it says...
But how does the supercomputer feel? The thought about what he has created has not crossed Merrinoe's mind, and that is his biggest mistake, because he finds himself championing the wrong "child" in this unusual science fiction footnote. This is a footnote because it will always be in the shadow of the other film to feature one of its characters, none other than Robby the Robot from Forbidden Planet. Reuptedly because the suit for Robby was so expensive to make, an independent production was put into motion to showcase the child-friendly character, which makes what they do with him rather odd.
There is a vague explanation for how Robby was able to go back in time to exist in the America of the nineteen-fifties, something to do with a time-travelling professor, the previous head of the project who we never see, but at first it looks as if the robot will simply be used as a lighthearted plaything for Merrinoe's son Timmie (Richard Eyer). Timmie is a disappointment to his father, in contrast to the over-achieving computer, and cannot even master the basics of chess, never mind mathematics, but Merrinoe would be better remembering that he should be encouraging the human side of things and not letting machine become the true master, as begins to occur here.
The first hint we get that all is not right is when the computer hypnotises Timmie into being a chess champion, which baffles his dad, but pleases him so much that he allows the boy to put Robby, who at the start of the film is a lot of dismantled parts, back together. Robby is incredibly advanced, and the computer knows it, so while he is enabling Timmie to fly in his own specially designed contraption or turning him invisible, the real power behind him is drawing up plans to exploit the current Cold War. The Soviets will, according to the computer, commence World War Three if they know about the space platform, which turns out to be precisely what it wants.
There are echoes of this film's mechanised menace in HAL 9000 from 2001: A Space Odyssey, in that neither trust the humanity that created them and both believe they know better, to the point that they will kill to complete their missions. In fact, for a supposed children's film there is a share of nastiness here which seems out of place, as if the script by Forbidden Planet's Cyril Hume was trying to teach the little tykes a harsh lesson in behaviour, with the under the evil influence Robby at one point even threatening to pluck out Timmie's eyes. In fact, the level of ambition for a film with a fraction of its predecessor's budget is unexpectedly high, dragging in as many modern for the fifties paranoias as it possibly can, without even bothering to lighten the tone with humour in the grim second half. No masterpiece, then, but better than you might have thought. Music by Les Baxter.