Thousands of years ago, an advanced civilization thrived on the surface of the earth. When the Great Cataclysm occured, most traces of this civilization were wiped out. The great city of Arkadia was swallowed up by the earth. The ancient Arkadians believed that they were the only survivors of the Cataclysm, and rebuilt their society deep in the center of the earth, depending on the powers of their artificial sun, the Tehra. Believing life on the surface had become impossible, the ancient Arkadians decreed that future generations should only know their home at the center of the earth, and locked up the city's Archives. The only being allowed in and out of the Archives was Tehrig, a sentient flying machine who made the Archives his home.
The search for Arkadia
The Arkadians would eventually regret the decision to keep their past a secret, as the Tehra began to fail, threatening the destruction of their city, and possibly even the world itself. A group of children, impatient with the Arkadian Sages' insistence on doing nothing, enlisted Tehrig's help, along with that of Bic and Bac--two talking anteater-like creatures, to sneak into the Archives to search for any information that could help them save the Tehra. They discovered that people did live on the surface once, and used this knowledge combined with the power of the Tehra to create a living replica of a being from the surface. She was named Arkana. The children presented Arkana to the Sages and told them of what they had discovered in the Archives. Hoping that they might be able to find help from the surface to save their world, Arkana, Bic, and Bac left Arkadia aboard Tehrig.
When they neared the surface, Arkana and company encountered Matt and Rebecca, a brother and sister who had been exploring an underground river in some caves near their home. The group were suddenly attacked by the Pirates of the Seas, who terrorize the worlds of the strata that lie beneath the surface of the earth. A wanderer named Spartakus, a skilled fighter armed with a versatile weapon worn on his wrist, rescued them. Pursued by the Pirates, unable to return to the surface, and having lost their direct route back to Arkadia, the group escaped into the strata aboard Tehrig. ("The City of Arkadia")
The group of friends journeyed through the worlds of the strata, avoiding the Pirates and other dangers, and searching for a way back to Arkadia. Spartakus, having traveled the strata for most of his adult life, acted as their guide and protector. He began to make some interesting discoveries about his own past as their journey progressed. The song Spartakus' father taught him to play on his mouth-harp just happens to be an old Arkadian song... ("The Drummer")
One time, while being pursued by the Pirates, they were forced to escape through a gateway that led to "Elsewhere and Tomorrow"--finding themselves not in another stratum, but in outer space. There they discovered an asteroid-like object that resembled Arkadia, and met Starkus, the "Star Healer," who kept secret from them the fact that Spartakus and Arkana were actually his ancestors, and that the Arkadians' destiny was to travel to the stars. Tehrig and the group returned to the strata, not knowing the truth about their future.
One of the most important discoveries made during the journey was an ancient mask with a special jewel "eye" in the center. When removed from the mask, the jewel transported the group to what appeared to be another time and place where a man named Arkshag claimed he could lead them to Arkadia. It turned out to be a trap, however, and Arkshag was leading them to a prison camp where those who defied the laws of Arkadia, refusing to let the past be forgotten and leaving their city to live in the strata, were held. The group escaped Arkshag, but the prisoners remained trapped. Spartakus made an interesting observation, noting that his father had known of this camp, and had reason to fear it. This raised further questions about Spartakus' father and whether he had some kind of connection to the Arkadians... ("The Prisoners of Lost Time")
Upon finally reaching Arkadia, the situation looked grim. The Tehra was losing power quickly, and there didn't seem to be anything that could be done. The group puzzled over the Archives, and began to wonder about the mysterious slab of metal--the Auracite--that stood facing the Tehra. As Spartakus approached the Auracite, his wristguard began to glow. The two mysterious objects were somehow connected, and when Spartakus moved closer and pointed the wristguard at the Auracite, the giant slab glowed and flew into the Tehra, re-igniting it.
Life on Arkadia soon returned to normal, and the group prepared to leave again. Matt and Rebecca reasoned that since time passes differently while in the strata than it does on the surface world, they would probably make it home in time for dinner. Bic, Bac, and Tehrig decided to join them and explore the surface world for a while. Arkana and Spartakus, having grown very fond of each other, vowed to stay at each other's sides in their future travels. The group left Arkadia toward the surface once more, but all was not as well as it seemed--there were many questions still unanswered, and something had been forgotten... ("The Secret of the Auracite")