The explorers encounter a baffling new phenomenon, which threatens to destroy the plateau.
A discovery reveals more of Marguerite's connection to the Druids and drives a wedge between her and Roxton.
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.
While protecting a crate of iridium ingots that were stolen from the Royal Navy five years ago, Lt. Drummond captures Challenger.
Challenger is the first human to test his experimental substitute for food and winds up in a duel with apparitions from his own mind.
Finn battles three demons who have taken the places of Challenger, Roxton and Marguerite.
When archaeologists are murdered on the plateau, each member of the Challenger expedition is a suspect.
Challenger experiments with a mysterious energy source, throwing the explorers into Earth's cataclysmic future.
An assassin linked to Marguerite's secret past drives her apart from Roxton and threatens the explorers' lives.
Veronica falls in love with a 19th-century musician, unaware of his tragic obsession.
Death takes the form of a beautiful woman determined to claim Roxton's soul.
A meteor plunges the Plateau into a new ice age which threatens the world.
A deadly attack forces Malone to relive his suppressed memories of World War I.
A powerful witch is bent on destroying Challenger and his science.
After crash-landing the balloon in an unforgiving land, Malone befriends a female warrior.
Stuck in the Old West, Roxton is pursued for a crime he didn't commit.
Roxton and Marguerite travel upriver to save their friends from Roxton's former mentor.
Malone becomes the link between a knife and the murders of Jack the Ripper.
To save Malone, Challenger and his team risk unleashing a supernatural killer.
Roxton becomes the prey of the ultimate hunter.
Marguerite joins a trio of dashing bandits with a deadly secret.
A deadly airship crash traps Challenger and his team seven years in the past.
An escape route opens to the expedition when an airship lands on the plateau, but the mysterious pilot has other plans.
The explorers experience a visitor from the past, who leads them to the edge of disaster.
Werewolves make life a nightmare in the treehouse; Challenger faces a scientific challenge when Malone turns beastly.
When Marguerite and Roxton kiss, the earth moves, and the explorers are launched on a wild treasure hunt.
When the explorers enter an ancient temple, they release supernatural forces which threaten to destroy them.
Roxton, Marguerite, Challenger and Malone are marked after touching an amulet, convincing them to return it to the cave.
Challenger, Marguerite and Ty set out on a rescue mission for Malone and Veronica.
Roxton and Marguerite are jailed, accused of robbery after walking through a brilliant light on the far side.
Alex, a kobold, takes Roxton, Malone and Veronica prisoner; Holt is constructing a uranium generator to allow the kobolds to live above ground.
Challenger, Marguerite and Veronica follow hunters tracks through gas defenses, looking for Challenger.
Danielle crafts a voodoo doll of Roxton, putting him in her control.
Gunfire shatters the lost world when trophy hunters try to capture a troglodyte child.
The Lost World is in the grip of a crippling drought.
Empress Centuria orders her Lizardmen to hunt and kill Tribune, who flees to the treehouse for help.
Veronica unwittingly releases a savage giant from captivity, and Marguerite and the others must use all their talents to subdue him.
The adventurers recover an ancient map showing the escape route from the Lost World.
Roxton and Veronica discover the alien invaders are skeletons the heroes have to fight.
Roxton saves a young woman and steps right into Balar's trap.
Roxton, Marguerite and Malone are strangely possessed by the spirit-wearers of their clothes.
Challenger tries to harness the energy of lightning.
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.
On a bridge spanning a deep gorge, a fierce battle unfolds with Drakul's raiders.
Drakul and the Raiders shoot down the adventurers' balloon, beginning a game of cat and mouse.
A Gypsy fortune-teller reveals a scary future.
Roxton and Marguerite must battle a group of evil Goths.
Norse warriors assault Roxton and abduct Marguerite.
A mummified corpse comes to life; a tyrannosaur pursues Summerlee.
Veronica reunites with her father; the team must fight Kartas, a bounty hunter after Veronica's father.
Travelers from the future arrive in the Lost World to manipulate history.
Challenger meets up with a former scientific rival; an old witch may have the key to an escape from the Lost World.
After slapping a young king, Marguerite must choose between instant death or marrying the boy.
The adventurers come upon the ruins of a civilization destroyed by an enormous explosion.
Roxton changes the lives of the Tintas when he kills a warrior from the Hikari tribe; a World War I flying ace crashes in the jungle and takes Marguerite, Malone and Summerlee as prisoners.
Veronica, Challenger, Malone and Marguerite find evidence of cannibals in the jungle.
Roxton, Challenger and Summerlee bring badly injured Malone to a magic healer in order to save his life.
The adventurers follow a map to a paradise that feeds off the lives of others.
Druids worship Marguerite, who bears the mark of an ancient prophet; Veronica and Summerlee find a baby.
Bitten by a vampire, Roxton attacks Marguerite and Challenger; a native falls for Veronica.
High Priest Tolmac preaches, and practices, the need for the guilty to find salvation in fire.
In order to free Challenger from her tribe, the team must retrieve the bones of a warrior queen's husband.
A giant bee stings Summerlee; Roxton, Veronica and Malone search for nectar to save his life.
When Roxton is running from a tyrannosaur, the earth suddenly swallows him up; the party follows a river to an underground ocean.
Ape men attack the tree house.
Challenger and his team search for a prehistoric world.