Six thousand years ago, the planet Beta III was torn apart by war, crime, and corruption. Then a visionary leader arose, Landru, who became a benevolent autocrat. He has maintained a simple, stable society that has survived since then without those "ancient evils". Enterprise is there to investigate the disappearance of the starship Archon in the vicinity a century earlier. It seems that Landru dislikes those who display individuality; they must be absorbed into "The Body" or destroyed. So it was with the "Archons" and so it will be with the Enterprise unless Kirk can defeat Landru. But will unseating him destabilize the society? Will it be a violation of the Prime Directive?