Passing a ringed planet that looks just like Saturn, the Odyssey receives distress signals from a disabled ship. Ulysses and the children rescue the pilot, and she tells them her name Hypsipyle is and she wishes to go to the base at Istria. She wants help in freeing the women of Lemnos, after all the men imprisoned them since they rebelled against their male masters. On Lemnos, it is the women who do all the work, and work in the factories producing Tridents for the Sharkmen. As punishment for her disobedience, the Lemnos Council of Four imprisoned Hypsipyle's father, the king of Lemnos. As Ulysses escorts Hypsipyle to Istria, she tells him that her father may know the location of the Kingdom of Hades. At Istria, they find the entire base has been destroyed by Tridents, so they then head off to Lemnos itself. There, they find the factories empty, with all the women still imprisoned. They free the women, but on board the Odyssey Yumi senses that they are in danger, and so she and Telemachus follow Ulysses. The Council of Four plead with the women to go back to work and finish the Tridents before the Sharkmen arrive. On Lemnos, the children encounter a third group, the dwarves, who are also compelled to work by the men, and are captured. Hypsipyle manages to free her father, King Thoas, while the women and the men engage in a stand-off. Hypsipyle, along with her father tell both parties to trick the Sharkmen into entering the Trident factory, which they will then jettison. As they begin to get rid of the factory, Ulysses is told that Telemachus and Yumi are still inside, and so he and Hypsipyle go back in to rescue them and quickly encounter the Sharkmen. King Thoas battles the Sharkmen's commander and is mortally wounded. Before he dies, Thoas tells Ulysses that the Kingdom of Hades lies beyond the Desert of the Tarters. Ulysses battles the commander, and everyone manages to escape from the factory just before it is jettisoned. As Ulysses and the children return to the Odyssey, the people of Lemnos are united in celebration of their freedom.moreless
The Sharkmen seen in this episode look very different from those who appear in "The Hidden Truth". One supposes that the Sharkmen fighters are split up into several different races, one of which appears in each episode.