Flash Gordon: The Greatest Adventure of All

Flash Gordon The Greatest Adventure of All is a 1982 animated television film produced by Filmation and written by Samuel A. Peeples, whose credits included the original Star Trek series.

Flash travels to find Zarkov and meets girl reporter Dale Arden, also on her way to interview him. They are bombarded by meteorites, which damage their plane and force them to bail out. On the ground they flee lava flows, and find a secret cave and a rocket ship. Doctor Zarkov, having no time for introductions, ushers them on board and they blast off. When safely in flight, he explains he is on a mission to the wandering planet Mongo to convince their rulers to call off their attack on Earth by force if necessary, using a gravity weapon of his own invention. For their part, Flash and Dale agree to help him.Before they can make contact, hostile ships shoot them down, and they make a crash landing. After barely surviving attack by a large predato, they are captured by animalistic savages and dragged to a giant idol to be sacrificed. They barely escape to the outside, where they meet King Thun of the Lion Men. ........

Source: Wikipedia