Spartakus and the Sun Beneath the Sea (1985)

While exploring a cave, Matt and Rebecca meet Arkana, who tells them of her mission. When the pirates attack, they are rescued by a mysterious warrior named Spartakus.

Tehrig is swept away by the powerful currents of the River of Time. The group finds themselves in a land occupied by a primitive tribe that is being threatened by the machines of an advanced civilization from the stratum above. Meanwhile, the children of Arkadia are trying to fix the entrance to the Archives, which has rusted shut.

Arkana is kidnapped by the Thot, a gigantic, well-meaning beast who lives in an abandoned metropolis.

In a crystalline strata that echos with the sound of the Tehra, the group meets Galileo and are taken prisoner by the Inquisitors, who try to get them to renounce their claims that other worlds lie beyond their stratum.

In a snow-covered land, Spartakus and his friends meet Mira and her grandfather and help them defend their village against the Mogokhs.

Massmedia teams up with Arkana and Tehrig to rescue Spartakus, Mighty Matt, and Sleazeappeal, who are being held prisoner by a tribe ruled by women.

The group tries to rescue the great orator Demosthenes from Nasty Max and return him to Athens to clear his name.

Pursued by the pirates, Tehrig travels to the ice-covered stratum of Icelandis, where one of the three legendary gateways to Arkadia is said to exist. There they discover the strange ghost ship Araukania III, which might be from an expedition that left Arkadia a long time ago, as well as other artifacts that suggest a connection between Spartakus' ancestors and the ancient Arkadians.

Having found the way back to Arkadia for them, Spartakus leaves the group. Nasty Max, however, soon captures the group and takes them back to the pirates' island, hoping that having Arkana and her powers will help him win the Inter-Marine Pirate Federation election. Spartakus must rescue his friends before they are sold into slavery.

Tehrig is damaged while traveling through a dangerous passage, causing him to believe he is still in Arkadia.

When Spartakus plays a song taught to him by his father, a drummer mysteriously appears and leads him on a bizarre journey. If Spartakus can prove he is the rightful heir to an ancient kingdom's throne, he is promised a meeting with his long-lost mother.

Matt discovers a strange mask that transports the group to another time and place. A man named Arkshag claims that he can lead them to Arkadia, but Arkana suspects it may be a trap.

Matt and Rebecca discover a parallel world that resembles their hometown, where a war has been raging for countless years. The only way to stop the fighting is to show both sides proof of Arkadia's existence.

Believing Arkana to be long-lost love, a mad scientist sends Tehrig back in time through the group's many adventures, in an attempt to bring her back to him. This episode is what's often called a "clip show", since it consists mostly of scenes from previous episodes.

The group finally reach Arkadia and try to solve the mysteries of the Tehra. Spartakus discovers that his wristguard may hold the key.