Maetel Legend: The Symphonic Poem of Destiny is a two-episode OVA series that tells the origins of Maetel, Emeraldas, and Queen Promethium. This series serves as a sequel to Queen Millennia and as a prequel to Galaxy Express 999.
After La Andromeda Promethium was crowned the new queen of La Metal after leaving Earth, years pass on with a successor coming into power. With La Metal no longer on its elliptical path, it relies on its artificial black sun. However the black sun is beginning to fade and the citizens of La Metal are beginning to starve. With people suffering, Queen Promethium has come into contact with mechanical lifeforms known as the Metanoids. A scientist from this group known as Hardgear gives Promethium the means to mechanize the planet and its people to ensure survival. Believing she does not have a choice, Promethium goes through the mechanization process only to find that Hardgear was only using her for his goals of domination. With the last of her humanity, Promethium sends her daughters Emeraldas and Maetel away on the 999. The sisters meanwhile have to fight off their pursuers while dealing with loss of their mother.