A group of scientists constructed a large extended vehicle with numerous technological capabilities, driven by intellectual young adults on a mission quest to travel the country, hoping to help restore what has been damaged by environmental (and man-made) disaster. They usually come across all sorts of humans, many hostile or underhanded, self-serving or barbaric, manipulative and cunning, with our young heroes trying to make a difference to the victims of these people. Terry Lester is tall blonde leader, Jonah, wise beyond his years, with a desire to teach others how to behave and learn from their mistakes, as well as, guide his traveling companions/colleagues, Ruth (Jean Marie Hon, sweet, with the whole Asian girl next door look and attitude), Samuel (José Flores), the teenage genius of the group, and talking monkey, Adam, who can actually win games against his human team at chess. Often one of the group (or multiple members) are in peril and need rescue due to the inhospitable, often dastardly antics of certain humans who haven't learned anything from what has happened to the world. In "The Flies", parentless children follow an unscrupulous vagabond, all riding in a horse-driven carriage, stopping off at places to pick up items they might need in order to sustain a meager existence. The orphans' leader, Master Fagon, often trades what he finds with other "tribes", but his presence is not wanted when near a camp containing savages (looking like rejects from The Road Warrior), known as the Warlords, whose area he often has the kids plunder for objects (garbage, really) that be of some use in getting food in exchange for them. Poison gas canisters (including some laughing gas, used later in a rescue mission) are found by the crew of Ark II and Jonah will try to talk sense into Fagon and the flies (their nickname) regarding the dangers of not disposing of them. But Fagon has plans to rule the Warlords by threatening to poison them
Two familiar faces from Lost in Space make appearances in this episode: Jonathan Harris, Dr. Zachary Smith himself, is the wily and untrustworthy Fagon and Malachi Throne is the leader of the Warlords (Throne showed up as a jewel thief right out of Aladdin during the laughable second season). Harris and his kids will return in another episode of the short-lived series, Ark II, causing more mischief and trouble for the crew of the traveling vehicle. Also appearing in this episode is the flying jet pack used by Jonah when he needs to personally observe from the air and low terrain service vehicle, the Rover, which can go places the much bigger Ark II cannot. Both often show up during the series as devices to help the Ark II crew in their missions, coming in quite handy during difficult situations. Harris, obviously a draw for LiS fans, seems to be having a ball, costumed as if a street pauper fallen on hard times. The filth and uncleanliness you often see of characters living throughout the rather harsh environs of a country beaten up by pollution and hot sun interestingly clashes with the squeaky clean crew of Ark II who have all the benefits that come with technology and science, the creature comforts they possess compared to what those living on what the land provides (and dead mankind left behind).