Scientists who create a new telescope use it to find that a star creature comes from space and attacks them. While the gang is driving, they have a flat tire. When Scrappy, Scooby, and Shaggy are fixing the tire, the Star Creature attacks them. Running away, they find the rest of the gang saying that they need to go to Star Laboratory. Arriving at Star Labs, they find the Star Creature.
Several times, they see it and it chases them. Eventually, Scooby and Scrappy run off into the woods and find a bear. The bear attacks them, but they run back to Star Labs. The Star Creature finds them and Shaggy backs up into the telescope controls. The telescope goes out of hand and hits the Star Creature. The creature lays there and the police show up to unmask it as Mr. Greenfield, owner of the observatory. He's been using the telescope to steal secrets from Star Laboratory. But when Professor Spaulding discovered a new star and worked on it for longer hours, that upsets Greenfield's plans. So he had to find a way to disrupt the professor's work. Greenfield was arrested soon after.