While being chased by a hobo, the castaways find themselves trapped by a force field. They then find a town without any people in it. They soon find out that the town was built by a lonely old man who built the town based on pictures he found on a ship that crash landed on the planet years earlier. They appreciate the old man's kindness, but still try to find a way to escape. Complicating matters is the old man's sadistic granddaughter, who is jealous of them and tries to kill them.

The castaways meet a supposedly amnesiac man from Earth. They decide to take him in against Steve's better judgment. It is soon revealed that the "little person" is a giant who has taken a drug to shrink himself down to the size of the earthlings. He eventually kidnaps Betty and takes her to their hideout with hopes the others will follow so they can be captured.

The crew finds a woman of their size while on a trek. Mark is attracted to her, who in return, invites him to her home. Burton tries to convince Mark that this is a trap set to become a guinea pig for the Giants.

Steve and Fitzhugh find a small cavern loaded with electronic equipment that appears to be what's left of a previous expedition from Earth. The race is on once the Giants become aware of the equipment's existence and try to recover it for their own needs.

The space travelers are stalked by bounty hunters when a reward is offered for their capture. One of them makes a chance discovery that could lead to a game changing weapon.

A giant scientist has invented a device that is to be used as a guidance system for their space program. Unfortunately, it is flawed and has failed a critical test. Mark, going against Steve's orders, decides to help fix the problem and in return the scientist promises to help them return to Earth. However, the wife of the scientist is jealous of Mark and feels that any help he gives her husband will help to discredit him and as a result she reports what is going on to Inspector Kobick.

Dan and Mark are sucked up in a vacuum-cleaner-like machine by Bolgar and Zarkin, of police security. Mark's shoulder is injured and he is unable to later escape with Dan.

Fitzhugh, looking for a giant seafood runs afoul of a giant deaf boy whose father is a poor fisherman. He manages to escape and Valerie and Betty return. They and Steve are forced to take refuge in a giant seashell, which the boy takes home.