The story begins with little Johnny decked out in his best Tom Corbett space gear, and his sister Carla who are scampering about some of the least interesting terrain ever put to film. They stumble upon a cave (filmed at Bronson Cavern, California) where two archeologists Roy and “The Professor” are trying to excavate a primitive painting off the wall. The Professor then abruptly lectures Johnny on the wonders of peaceful coexistence and the benefits of science to society. The children’s mother and older sister Alice show up and drag the children off for lunch and a nap atop some terribly uncomfortable looking rocks. You really have to see these rocks they’re trying to sleep on.

The rocks are so bad that Johnny can’t sleep. He gets up and goes back to the cave, and stumbles, tumbling down more rocks. (Rocks are important in this movie). When he recovers from the fall, he is launched into a world of visions and the viewer is launched into Robot Monster‘s true character of insanity. Johnny watches earthquakes that rock the world, a pair of Claymation triceratops who appear to be trying to have Claymation sex, and an alligator with a fake dorsal fin who battles a Tyrannosaurus Rex, badly portrayed by a monitor lizard.

Johnny escapes from these pointless visions and rushes to the cave, which is filled with electronics. There he gets a glimpse of one of the greatest screen menaces of all time: Ro-Man, agent XJ-2, a “Robot Monster”, the ultimate instrument of destruction from the Planet Ro-Man. This killer from outer space looks suspiciously like a gorilla with a deep-sea diver’s helmet decorated with TV aerials but he is the fierce danger that threatens our science-friendly, picnic-loving heroes.

Ro-Man waddles to his communicator, a revamped WWII radio with a video screen on top that blows bubbles when it operates, and calls his galactic boss, the Great Guidance. The two then converse in bizarre minimalist techno-babble that would make any Star Trek scriptwriter proud. Guidance reports that there are no other forms of life in the universe and that Earth is their only rival for galactic supremacy. So, these two space villains develop the plan to wipe out mankind.

Ro-Man then reveals that he has already started stage one of the operation and tricked the world into nuking itself to death. After the atomic fallout settled down, he revealed himself and mopped up the survivors with his Calcinator Death-Ray. He claims success but his boss points out an error and says there are eight people still running loose. By the sheerest coincidence, these eight, the very last of mankind, are near the cave having a picnic. Ro-Man promises to wipe out the human plague.

Johnny rushes “home”, now a bombed-out basement surrounded by electrical wires. The Professor and Mom scold him for wandering outside the electrical barrier (obviously the purpose of all the wires). Johnny reveals that Robot Monster inhabits the cave and is in the local neighborhood. The Professor, who may or may not be Johnny’s dad, can’t believe such an amazing coincidence, although there are many in this film. Another is revealed at this point in which the audience learns that he also created a super immunity serum that he tested on the entire family and saved them from the fallout from the nuclear war Robot Monster covertly started. Mom is also a genius because she invented the electrical barrier that protects the family from all dangers.

With these brilliant minds they ponder their situation and come up with the only possible conclusion.

They’re doomed!

Unless they can find a weakness in Robot Monster …

Little Alice then suggests that perhaps the soldiers on the orbital space platform, a veritable garrison of fighting power, might have been overlooked and forgotten by Robot Monster. If they could communicate with it, then the soldiers could come and kick the Hell out of the alien menace.

They all turn to the video screen, which activates.  It’s not the space marines. It’s Robot Monster, who informs them that they are the last humans alive and that if they surrender, he promises them a quick and painless death. They refuse and he promises them a painful death instead. At this point we learn that there actually are two settings on the death ray – painful and not.

After some more needless discussion, Roy tells everyone that Jason and McCloud are also still alive. Who are they? (Believe me it won’t matter in about five minutes). Jason and McCloud have been off with batches of the Professor’s super serum. They scrounged enough fuel together to launch a rocket to the Space Platform that carried the serum with an invitation to come back to Earth and kick a little Ro-Man ass.

Yet, these hopes are dashed as Robot Monster calls them again and gloats that he detected the rocket launch and then blows it up in a scene that looks remarkably like older V2 rocket test footage. He then shows them the space platform, portrayed by an amazingly cheap-looking model spewing sparks and swinging in an erratic circle. That also blows up but fortunately causes no harm to the very visible hand holding the model. Robot Monster repeats that they have no hope and surrender is the only solution.

Devastated by the turn of events, the family weighs their options and decides to appeal to the space invader’s mercy. They call Robot Monster back on his video communicator.  The alien demands that they state their business because he’s busy. (What he’s involved in other than exterminating mankind isn’t clear). The Professor defiantly declares that they will never give up and humanity will survive! Besides, he asks, “What exactly do the Ro-Men have to fear from humans?” Robot Monster provides the standard “humans are self-destructive so we can’t allow you to tamper with affairs in the cosmos, blah, blah, blah, etc. etc. etc. excuse.

Undaunted, the Professor introduces the family. Robot Monster isn’t interested until Alice takes her turn in front of the view screen demanding peace with honor. At this point we learn that Robot Monster has some biological urges that he can’t quite understand and these start to cloud his logic. He offers to spare the humans if Alice will come and just “have a chat” with him.

Robot Monster then goes out and runs endlessly up and down a hill for no understandable reason while little Johnny rushes out to face the invader. When Johnny arrives, Robot Monster aims his Calcinatory Death Ray at him but, surprise, the super serum protects little Johnny from that as well as it protected him from radiation. Robot Monster realizes his error, relies on his superior skill and intellect, and opts to simply use force. Johnny runs home and is sent to bed without supper for his transgression.

Meanwhile, Roy and Alice decide to get married and the Professor, using powers given to professors after nuclear conflicts, marries them. The two newlyweds go off to share some private time together. Everyone is happy, except Robot Monster, who bursts in and kidnaps Alice and takes her back to the cave, but not before also finding little Carla out in the open and squeezing the life out of her in a fierce space gorilla bear-hug.  The family discovers Carla’s body and buries her just before Roy stumbles into the scene, announces that Ro-Man has captured Alice, and then dies on the spot.

Back at the cave, Robot Monster again calls Guidance and explains that he should keep one of the humans (Alice) for study. Unimpressed, Guidance orders him to kill them all and cuts the transmission. Robot Monster professes his love for Alice. She resists so he starts pawing at her, ripping her top and exposing her shoulders. He tries to take it further but his communicator starts ringing. He snatches some rope and tries to tie up Alice but when this fails, he simply knocks her unconscious.

Robot Monster turns on the video display and sees the Professor who says they agree to surrender and are ready to die. Robot Monster says he’s busy and to call back later then hangs up and turns his lustful attention back to Alice, who miraculously managed to tie herself up while unconscious.

He moves towards her but the communicator goes off again. This time it’s the Great Guidance and his patience is at an end. Robot Monster begins to question the Guidance’s instructions asking why they can’t be like the humans, and laugh, and want, and dream? Guidance is fed up and orders Robot Monster to kill the girl and then the others. In response, the invader simply mutters “I cannot” over and over.

Johnny rushes into the cave and presents himself to Robot Monster as a diversion. Guidance insists that Robot Monster snap out of it, kill the girl first and then the boy. The alien asks Alice to forgive him and throttles little Johnny to death. Enraged by Robot Monster changing the order of his instructions, Guidance activates the Calcinator Death-Ray and kills Robot Monster who falls and dies right next to Johnny. Yes, two children under the age of ten are slain in this 1950s film.

… but wait …

The screen dissolves and we’re back in the original reality. Roy finds Johnny who has suffered a bump on the head from falling on a rock and carries him back to the cave where he happily learns that the world isn’t under attack by space aliens and suffering from total nuclear devastation. Luckily, it was all a dream.

… or was it …

The soundtrack turns ominous and Guidance stalks out of the cave, not once but three times for emphasis!

Robot Monster is a legend among the B-movie brethren. George Barrows was well known at the time as the one of two guys with the gorilla suit. He and Bob Burns played practically every gorilla in Hollywood for a couple of decades.

Ironically, given the complete lack of budget used in this film, the musical score was composed by Elmer Bernstein, who went on to produce such classic scores as “The Great Escape” and “The Magnificent Seven”.

Word of this tragedy soon got out and the film was an incredible failure, although its low budget of $20,000 has paid endless dividends to the copyright owners since the movie’s first run. The film was re-released in theaters intermittently throughout the 1950s with the new titles “Monster from Mars” and “Monsters from the Moon”. Since its first showing, Robot Monster and its director were so universally scorned and derided by reviewers that Phil Tucker was blackballed from the industry and never again worked in the film business.

The saddest part of this film is that Phil Tucker really did believe he was creating art. The dialog is filled with social and political references that he thought relevant at the time. Unfortunately, unlike other science fiction movies that successfully used this approach, this film utterly fails to make any points at all. It’s just a disaster, throughout every second of its 66 minutes of playtime.

That’s probably why it’s also a huge cult classic that’s a blast to watch!