He-Man and the Masters of the Universe is an American animated television series produced by Filmation and based on Mattel's successful toy line. The show, often referred to He-Man, was one of the most popular animated children's shows of the 1980s, and has retained a heavy cult following to this day. It takes place on the fictional planet of Eternia, a planet of magic, myth, and fantasy where the lead character, Prince Adam, uses the Power Sword. When he holds it aloft and says the magic words "By the Power of Grayskull, I have the Power!" he is transformed into He-Man, the most powerful man in the universe. Together with his close allies, He-Man defends Eternia from the evil forces of Skeletor.