Synopsis: The Free-Fall Warriors are a team of stunt flyers participating in the Festival of the Five Planets. The Doctor catches up with noted science fiction author Dr. Ivan Asimoff to watch the show. The only problem is that there are actually six planets in the system. The sixth is in open rebellion against the other five, and has now sent an attack squad descending on the Festival.
When the Doctor and Asimoff agree to go on a test flight with the Free-Fall Warriors, they find themselves victims of a sneak attack by agents of the sixth planet. Their pilot, Machine-Head, sends out a distress call to the other Free-Fall Warriors, warning them of the sixth planet's attack. The Warriors give pursuit, and are able to take down and disable the sixth planet's pilots. The Warrors return home to a heroes' welcome.