Voltron: The Third Dimension

Years ago, the Voltron Force ultimately defeated Prince Lotor, resulting in his horrible disfigurement and Voltron being retired. But before Lotor was captured, he sent Castle Doom away to an unknown location. Now in the present, Keith, Allura, Amalgamus and a supposedly reformed King Zarkon are trying to learn from Lotor where Castle Doom went. Meanwhile, space pirates have reemerged and begun attacking Alliance ships and colonies.

With Lance saved, the Voltron Force are heading back to Arus. They have to stop Zarkon, however with their robot lions destroyed, they're at a great disadvantage. But Queen Ariella reveals to them a way to bring the lions back.