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.
The Earthlings are forced to compete in a life-and-death chess game with a Giant chess expert. The little people find themselves bound to the chess pieces.
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 ...
A Giant scientist experimenting with cloning technology succeeds in cloning Valerie and Barry. These are returned to the camp where they prepare a booby trap to kill the rest of the Earth party.
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 ...
Steve and Fitzhugh attempt to return to Earth in a spacepod, but travel back in time to the year 1900 where the local villagers decide they are being attacked by warlocks.
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 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.