Trying to track down the crew of the downed Federation starship Beagle, Kirk, Spock and McCoy arrive on a planet populated by a society that mixes savage ancient practices with 20th century technology. Enemies of the Roman Empire-like state are rounded up and forced to participate in televised coliseum battles. Kirk and Spock briefly encounter a peaceful group of people, but all are captured and prepared for their duels - including one event which will pit Spock against McCoy. Kirk must hope that he and his landing party can survive long enough for help to arrive from the Enterprise.