Description: The women of the planet Lemnos are being forced by the Shark Men to build the Trident ships for the gods. Princess Hypsipyle of Lemnos asks for Ulysses' help. But the children discover that another group also lives on Lemnos. The Odyssey picks up a distress signal from a disabled ship, when Ulysses rescues the pilot she tells them that she is Princess Hypsipyle - daughter of the King of Lemnos. She asks Ulysses to take her to the base on Istria because she seeks help to free the women of Lemnos who have been imprisoned after rebelling against their male masters. She reveals that the women of Lemnos work in the factories making the Trident ships for the Sharkmen, that her father has been imprisoned for her disobedience and that he may know the way to Hades. When the Odyssey reaches Istria they find that the base has been destroyed by the Tridents so go to Lemnos itself. There they find the factories empty, the women imprisoned and the children discover a third group lives on the planet - the Dwarves.