He-Man and the Masters of the Universe Season 1 Episode 37
Queen Sybilline, apparently once one of the most evil sorceresses in Eternia, has defected to the side of good. She enlists the help of He-Man and his companions in restoring King Danton of the Isle of Tears to the throne, having helped the evil Gorgon to overthrow him. But will they succeed, when Gorgon has recruited Evil-Lyn as his replacement sorceress?
Episode Title: The Defection
Air Date: 1983-10-25