A young alien (David Love) falls for a pretty teenage Earth girl (Dawn Anderson) and they team up to try to stop the plans of his invading cohorts, who intend to use Earth as a food-breeding ground for giant lobsters from their planet. The invaders, who arrive in a flying saucer, carry deadly ray guns that turn Earth-people into skeletons.
Derek (Derek Love), a teenaged alien guy, among a small crew of extraterrestrials in a little silver flying saucer, has come to Earth on a "seeding" expedition where "Gargons" (the alien world's foodsource animal) are to be exposed to the atmosphere in order to note their reaction to the new world's air. If they are able to thrive, millions more of the creatures will be brought to the planet to grow, and eventually be harvested for their flesh.The crew are from a totalitarian world where children are raised without parents by the state, where freedom of thought is suppressed, and empathy mocked. The killer instinct is paramount, as shown by Thor (Bryan Grant), who kills a wandering pet dog ("Sparky") which approaches after hearing the landing saucer and, as the crew disembarks, a stern associate of Derek called Thor (Bryan Grant), is startled by the barking critter, and draws his silver ray gun and disintegrates the flesh from the dog, leaving a falling mass of bones.Derek, meanwhile, examines the bones of "Sparky", and notices a metal tag with his name and address stamped on it. He brings this detail to the attention of the ship commander (Robert King Moody), saying that it signals intelligent life on this world. Derek wants to return to the times pictured in a book when there were families and love. The captain tells Thor to keep Derek under watch after taking his book away – Thor tells him that he'll be executed soon. Meanwhile, the Gargons first seem to fail the test, having a negative response to Earth's atmosphere, but the creature then revives, and its cells divide even faster than expected. Earth will be a perfect place to breed these fast-growing, flesh-eating monsters. Moreal (Ralph Lowe) calms Thor down and tells him that the gargons will be picked from the air. The captain speaks to the alien Leader (Gene Sterling), who tells him to kill Derek if he keeps on being a nuisance.Derek, who has turned against the authoritarian beliefs of his home world through contact with a forbidden book (which he brandishes at the crew to explain his baffling change of heart), rebels against unleashing
the killer Gargons on Earth, since they will attack higher beings, but the crew members all scoff at his weakness.
Derek escapes to try to warn Earth.Derek speaks with a gas station Attendant (Carl Dickensen) who directs Derek to the Morgans'. A driver (Billy Bridges) gives him a lift. Grampa Morgan (Harvey B. Dunn) is told by his niece Betty Morgan (Dawn Anderson-Bender) that Derek wants to rent the room of the brother who has just gone away to start a new life with his wife. Derek is surprised that Betty has known her siblings. Betty shows Derek his room. Thor has been also given a lift by another human (Billy Bridges) who explains the pieces within the car. Grampa accepts Derek as a boarder until he finds a job. Betty gives Derek her brother's left-behind clothes.Joe Rogers (as Tom Graeff-Lockyear) talks to Betty and drives away. The petrol station attendant tells Thor where the other guy who dressed like him went. Thor kills the attendant and his driver and drives away. Betty is teaching Derek how to drive. They meet Alice Woodward (Sonia Torgeson), a blonde bombshell who's swimming in the pool. Finally, Betty notices Derek's name tag. Betty is appalled. Thor talks to Grampa, who's watering the plants. Derek and Betty go to the landing site in the middle of the desert, where Sparky's bones still are.Thor also meets Alice, who is rude to him and swims away, and Thor kills her. Betty leaves a not to her sleeping grandfather. He's woken up by Joe, who's a journalist. Joe is Betty's boyfriend, and he's investigating a double murder. Grampa tells Thor that Derek and Betty have gone to Prof. Simpson (James Conklin)'s office and her secretary tells them he hasn't arrived yet. Thor reaches him first and kills him. Then, he jumps from the window. Derek, Betty and his secretary find the skeleton. Betty is worried about Grampa and tells him to go to the police. Grampa hides from Thor and leaves through the back door.The police fight Thor. Mac (Jim MacGeorge) wounds Thor. Harry (Kent Rogers) leaves after him. Betty talks to Joe and he talks to Grampa. Derek picks up a gun. Thor was hiding in a car, forces Betty and Derek inside the car and they go to see Dr. C. R. Brandt, MD (Frederick Welch), who was about to leave. Thor tells him to take away the bullet. Thor didn't kill Derek because he's the son of their leader. Thor wakes up sick but without the bullet and alone at Brandt's office. Thor faints. Nurse Morse (Helen Sage) tends to Thor, so she can't pick up Brandt's call.Thor takes Morse hostage. Mac and Harry go to look in a cave where the aliens have left the fast-growing lobsters. Thor and Morse also go there. Morse steers and saves Harry's life after the gargons had killed Mac. Thor beats Morse and drives after Harry. Morse wakes up. She jumps from the car which falls off a slope. She talks about the monsters at the cave with Harry.Betty realises that Derek is an alien. She thinks that he looks like his grandfather when younger. Derek decides to stay at planet Earth. They frenchkiss. Betty wonders why there are no crickets making noise. Suddenly, the monster lobster attacks her. Derek throws a stone at he and then they both drive away. A search party is killed by the huge black lobster. It makes the front page of the newspaper. Derek knows that the beast will end up attacking the city, if only for food. A man (Robert "Bob" Regas) calls the police about having seen the monster. A news caster (Robert Williams) gives the news, and says that everybody is evacuated except for Derek and Betty.Grampa is still looking for Betty. Joe will help him. Betty and Derek find the monster. She tells an electricity generating-plant technician (Don DeClue) to turn the power on at the right moment when Derek has put a wire around the monster. The technician gives more and more power until the monster dies.Derek needs to leave before Grampa and Joe arrive, as Betty will stay with them. Derek drives away but remembers sentences said to him. Betty tells Grampa and Joe about Derek being an alien, and the monster, and the psycho killer who had been going around killing people. Derek is at the Morgans'. He doesn't even say goodbye to Betty. He will go to hospital searching for Thor. Harry is taking Thor away from hospital. Derek takes Thor at gunpoint. He tells Thor that he won't kill humans because they'll be dead soon enough. Meanwhile, Grampa and Betty look for Derek in the desert. Betty, Derek, Joe, Thor and Grampa see the spaceship land in the desert. Betty cries because Derek is leaving him.The captain and the leader are there. They need to go back fast because Derek hasn't been the only one who read the book, and a revolution may arise if the leader is not in the planet. On the other hand, the leader admits that Derek is his son, and that he's been following him from afar. Derek enters the spaceship cheating his father, his captain and Thor outside. He tricks the other spaceship with the dangerous animals into going faster when entering the atmosphere and crashing onto the ground. He sacrifices himself for the Earth's well-being and dies.Betty, Grampa and Joe survive because they hide in the cave. They walk out of the place. —written by KrystelClaire