Simplify the following text for a Grade 5 native English-speaking person.
Original: The show takes place on the fictional planet of Eternia , a planet of magic , myth and fantasy . The show 's lead character is Prince Adam , the young son of Eternia 's rulers , King Randor and Queen Marlena .
Simplified: It was based on a popular toy line and told the story of Adam , who was prince of the planet , Eternia .