A huge robot that is even bigger than many of the giants that the castaways have encountered accidentally destroys a store and in the process kills a policeman. Steve, Mark and Fitzhugh, who were scavenging for food and supplies witness this and in the process Mark and Fitzhugh are captured. They are then brought to the laboratory of its creator Professor Gorn who offers to help them return to Earth if they can help him fix the flaw in his creation. They eventually do and the robot works perfectly. Unfortunately, Gorn double crosses them and decides to turn them over ...
While visiting a racetrack to gather horsehair to be used for cables for the electrical system, Fitzhugh gets a case of gambling fever. He decides to use his horse playing knowledge to place a few bets using a bum as an intermediary. Unfotunately, a track security official finds out what's going on and starts hunting down the castaways and winds up capturing Mark, Valerie and Betty.
A musician, threatened by thugs for a money debt, abducts Valerie and Barry and wants to report them to S.I.D. for the reward. Fitzhugh who escaped brings Dan, Steve and Mark to free them. However, the musician has second thoughts and hesitates about reporting them, but when Dan encounters the Giant, he suggests the way he can be successful is to being shown some jazz lessons. The thugs are suspicious of this new talent improvement and tries to exploit him. In the meanwhile, Fitzhugh is also abducted by the musician's strange neighbor: a snake charmer !
A penniless man wants to kill his uncle once he puts him on his will. Knowing he collects all kind of weird gadgets, he purchases a music box with a doll dancer. However, once he notices Valerie, he abducts her and put her in the cage as he asks to dance in the cage for her uncle. The little people gets aware of this, but also knows that the man has put explosives under the music box, putting Valerie's life in danger.
While playing with a giant dog, Chipper is injured when the dog sneezes and it causes him to hit a wall. Against Steve's orders, Barry, along with Val, goes to the veterinarian's office where the dog is being kept. They then meet his young assistant who agrees to help save Chipper. Unfortunately, the vet's lazy son finds out and holds Barry and Val hostage. The young man also was responsible for the dog that Chipper was playing with to run away. Now Steve, Mark, Dan and Fitzhugh must not only save Barry and Val, but also find the giant dog, which was a valuable movie ...
The little people become involved with a group of jewel thieves operating from a spooky wax museum. Tensions rise as the crooks fall out over a missing diamond, the whereabouts of which is known to the little people.
Some of them meet a suicidal actor who was once a great horror movie actor. He captures them and plans to offer them to a movie studio to use in a movie. After being turned away by every studio he turns to a disreputable director. The rest follow them and tries to free them.
A pair of time travelers from Earth's distant future are sent back to the past by their superiors on a mission of observation. However, the pair use the trip to plot for the eventual takeover of Earth in the future by wiping out most of mankind with a deadly virus and using the planet of the giants as a staging base. They eventually run into the castaways and use them as unwitting accomplices to their plot. Eventually Steve, Mark and the others find out the pair's scheme and try to stop them before they change mankind's future.
While the castaways are collecting fireworks at a carnival for gun powder to use to make explosives, Barry is injured when a young giant boy shoots off a roman candle. Steve, Mark and Valerie take him into a miniature balloon gondola to keep him from getting hit by more sparks, but the balloon is accidentally released and heads for the sky. They immediately are caught in an incredible windstorm and are taken to the other side of the planet where they find a society run by the dictator Titus. Titus can't believe that there is another society on the other side of the ...
The little people come upon a friendly giant who mistakes them for leprechauns. The giant, O'Reilly, assists the little people in obtaining items to help repair their ship, and the group becomes embroiled in a series of adventures with policeman Krenko.
While working on a small nuclear reactor invented by a sympathetic giant scientist, the castaways are accidentally exposed to strange radiation that causes them to seemingly vanish or experience wild hallucinations. They then try to find a way to alleviate the symptoms. However, while Steve, Mark and Dan are away, an impatient Fitzhugh activates the device and it gets dangerously close to critical mass.
The travelers come across a bizarre giant capable of hypnotizing people with his mysterious flute which, when played, can draw people magically towards it. The little people become involved after the piper attempts to abduct a giant child.
The little people witness a battle between several giants involving a mysterious new weapon, the owner of which subsequently disappears into a cave. It transpires that he is from a secret underground society which lives beneath the surface of the planet.
The group meets a giant inventor who has developed a new device, a teleporter, capable of matter transport over great distances. He is helpful and interested in the little people's problems, but is betrayed by an S.I.D. agent and must face the consequences.
The little people are attached by a giant boy who has been playing with his imaginary friend in the woods with an army of deadly military toys. The boy does not believe the earthlings to be real and carries on firings at will.
The Earthlings help a friendly puppeteer when he is injured by performing as marionettes at a carnival, but the owner suspects that the aliens are the real star of the show and plans to capture them for the reward.
Steve and Dan meet up with a pair of time travelers from another planet. The two pilots wind up stealing the device the pair uses for their travels and use it to go back to the day the Spindrift crashed on the planet of the giants in order to prevent the accident from happening. However, the two time travelers have followed them and warn the pair that if they do change history there is a good chance that when the Spindrift crashes that this time no one will survive.
Twin evil brothers - one at each end of the planet - plan to use an alien device they have found to gain control of the planet. The device needs critical repairs that only the little people are small enough to accomplish.