Spartakus and the Sun Beneath the Sea (1985)

The group returns to Arkadia to attempt to free the Prisoners of Lost Time but discover that the Tehra will never be permanently restored until a riddle is solved and a second auracite is found.

The group is forced to battle in a real-life chess match against some of their most fearsome enemies.

Matt follows a devilish trickster and his supernatural pets, a giant eagle and a teleporting snake, on a dangerous quest to find "the gold at the earth's core", thinking it may be the second auracite. Spartakus, knowing that no one has ever returned from the journey, tries to stop him.

While crossing the deserts of Barkar, Spartakus recalls the incident that took away his family and forced him into slavery, his life as a gladiator, and the bitter reunion with his long-lost brother.

Ringnar holds Tehrig prisoner, forcing his triggies to build new luxury high-rise apartments for the pirates. When Nasty Max discovers what Ringnar is up to, the two begin a power struggle for the control of Tehrig, the tower, and the pirates' loyalties.

The travelers meet Tutankhaton, who is about to become pharaoh, and are caught up in a plot by the boy's uncle and the Priests of Amon, who want to seize power and return to worship of the old gods.

When the pirates capture just about everyone on the seas, the group find themselves prisoners in the hold of the pirates' ship. Meanwhile, Bic and Bac have to deal with being forced to work as Massmedia's musicians and trying to recover Spartakus' wristguard from the pirates' casino, all while trying to avoid nasty pickpockets.

The group befriends a city of people descended from the original Arkadians. They use their shapeshifting powers to help rescue Arkana from a pirate trap.

The travelers are aided in their search for an underground vein of metal that may be auracite by a powerful but suspicious magician called the Manitou. Along the way, they encounter a Cherokee from the surface who is looking for a new home for his people.

Guided by a mysterious mute woman, the group ascends a large tower filled with recorded knowledge from throughout history, but someone is trying to keep them from reaching the top.

The travelers are caught in the web of a giant spider. Bic and Bac are held captive by a tribe of their anteater cousins for their fire-making ability.

The group returns to Mira's village, which is preparing another confrontation with the Mogokhs. The villagers are divided over a plan to buy peace with the Mogokh leader by giving him a large ransom of gold. Spartakus helps with the plan, hoping he can learn something about his father from Baatu.

The travelers investigate the stratum where the People of the Deep mysteriously vanished long ago. To help Tehrig stay on course in this area, which has magnetic disturbances, they create a fake competitor to FIPIRATE, tricking the pirates into increasing their broadcast signal strength. Of course it also causes the pirates to put on a huge impromptu concert for all the rogues of the strata.

The group investigates a city closed in by giant walls and are captured by the army of Iron Men, who terrorize its citizens. With the help of an eccentric genius named Uncle Albert, they plot to help the people escape.

A badly damaged Tehrig returns to Arkadia for repairs and soon begins thinking he's actually the pirates' ship. His friends try to bring him out of his delusional state, while recounting some of their adventures involving the pirates in "clip show" fashion.

The travelers discover an abandoned city that was once inhabited by the Arkadians who built the Tehra. Rainbow is here, too, and he wants the secrets of the Arkadians, as well as Arkana, for himself.

Tehrig is stuck in an ancient trap designed to disable ships run by artificial intelligence. Fortunately, the pirates are vacationing nearby, and Rebecca, Bic, and Bac try to steal the pirate ship to rescue their friends, with a little help from Ringnar's mischievous nephews.

Tehrig lands on an island inhabited by slow-witted dodo birds that can draw people into their dreams of flight. Rebecca gets lost after the pirates try to catch the birds and finds herself at the home of Alice, who lives alone with her memories of Wonderland.

The travelers discover the explorer Ulysses adrift at sea and help him reach the lost island of Atlantis, which only reappears once every one thousand years.

The group discovers an Aztec-like pyramid hidden deep within a mountain fortress. They meet a priest who intends to save the sun of the Civilization of the Condor by offering Arkana as a sacrifice.

The group returns to the city where Arkana was kidnapped by Thot in order to reunite it with its mother and return it home. But the pirates have built a theme park in the city, with Thot as the main attraction.

Tehrig is trapped by Arachne's web, and to free his friends, Spartakus has to board the ghost ship Araukania, where he agrees to guide the ship on its final journey to the Gateway to Dawn.

Having returned to Arkadia, Spartakus decides that the only to find the secret of the auracite is to go to Arkshag's prison camp, even if it means he can never return. Arkana tries to stop him, but Arkshag prevents her from reaching him in time. Inside the camp, Spartakus discovers the secrets of the oracle and his wristguard.

Spartakus returns to Arkadia with the Prisoners of Lost Time. Together, they discover the truth about the second auracite and Arkadia's original purpose. Matt and Rebecca return home as the Arkadians fulfill their destiny.