Challenger experiments with a new fuel source in the hot air balloon and takes the other explorers along for a test ride; however, a storm drags the balloon into a dangerous underground world.
A powerful witch is bent on destroying Challenger and his science.
Suffering from the effects of a poison dart, a hallucinating Malone believes he's back in World War I.
A meteor plunges the Plateau into a new ice age which threatens the world.
Death takes the form of a beautiful woman determined to claim Roxton's soul.
While protecting a crate of iridium ingots that were stolen from the Royal Navy five years ago, Lt. Drummond captures Challenger.
After touching her mother's pendant to a stone monolith, Veronica relives the last days she spent with her parents, discovering their fate and her own destiny.
A discovery reveals more of Marguerite's connection to the Druids and drives a wedge between her and Roxton.
The explorers encounter a baffling new phenomenon, which threatens to destroy the plateau.
The friends emerge from battle to find that one of their number is lost, and goons have enslaved a village.
While Roxton, Malone and Challenger are looking for a way off the plateau, Amazon women save them from an attack by a flock of pterodactyls.
At a haunted castle, the adventurers seem compelled to re-enact a romantic story of intrigue -- one that could end in death.
Roxton saves a young woman and steps right into Balar's trap.
Dinosaurs are behaving oddly, but the crew knows something is really wrong when Marguerite is nice to everyone.
An ancient map outlines an escape route; now the adventurers must prove to skeptics all they have seen.
A mysterious old woman, a shape-shifter, appears to Veronica, convincing her that her lost parents are safe in El Dorado. The woman gives her the directions to its entrance in a rock wall, and warns that she must tell no one and can never return. When Veronica unwittingly releases a savage giant from captivity, Marguerite and the others must use all their talents to subdue him again.
Captured by lizard men, Malone, Marguerite and Roxton are forced to fight as gladiators in the arena.
A woman who has saved the band from thirsty raptors will die if she cannot return immediately to the cave of the fountain of youth.
Marguerite recognizes as a trophy hunter a man who claims to be part of a Zoological Society rescue party.
Danielle crafts a voodoo doll of Roxton, putting him in her control.
Challenger, Marguerite and Veronica follow hunters tracks through gas defenses, looking for Challenger.
Alex, a kobold, takes Roxton, Malone and Veronica prisoner; Holt is constructing a uranium generator to allow the kobolds to live above ground.
Roxton and Marguerite are jailed, accused of robbery after walking through a brilliant light on the far side.
Aliens capture Veronica and Malone, forcing them to work in the mines alongside androids that have developed humanlike emotions and individuality.
Roxton, Marguerite, Challenger and Malone are marked after touching an amulet, convincing them to return it to the cave.
When the explorers enter an ancient temple, they release supernatural forces which threaten to destroy them.
When Marguerite and Roxton kiss, the earth moves, and the explorers are launched on a wild treasure hunt.
Werewolves make life a nightmare in the treehouse; Challenger faces a scientific challenge when Malone turns beastly.
During a thunderstorm visions of Summerlee, their lost colleague, lead the friends to the brink of destruction.
An escape route opens to the expedition when an airship lands on the plateau, but the mysterious pilot has other plans.
Scientist and explorer George Challenger learns from a dying colleague of a prehistoric world and organizes an expedition to find it.
Desperate to escape and more than a little greedy, Marguerite offers Veronica to a tribal chief in return for jewels and safe passage off the plateau for her group.
When Roxton is running from a tyrannosaur, the earth suddenly swallows him up; the party follows a river to an underground ocean.
Stung by a giant bee, Summerlee lies near death; Challenger seeks a way to repel an attack by the ape-men.
In order to free Challenger from her tribe, the team must retrieve the bones of a warrior queen's husband.
Challenger meets up with a former scientific rival; an old witch may have the key to an escape from the Lost World.
Travelers from the future arrive in the Lost World to manipulate history.
Veronica reunites with her father; the team must fight Kartas, a bounty hunter after Veronica's father.
Ramses, a vivified mummy, enlists Marguerite, Challenger and Malone to help him regain the Egyptian throne; a grieving dinosaur targets Summerlee.
Roxton (William Snow) promises a teen's dying mentor to help the boy fulfill his destiny as savior of his people.
A gypsy fortuneteller's visions eerily come true, leaving the band to fear for Malone's life. With William Snow, David Orth, Rachel Blakely and Jennifer O'Dell.
Drakul and the Raiders shoot down the adventurers' balloon, beginning a game of cat and mouse.