The protagonist of "In the Penal Colony" is an explorer from Western Europe who travels the world to observe other cultures. He finds in the penal colony a system of justice so strange, grotesque, and unjust to him that it challenges his usual guiding principle of never intervening in what he sees. Both the officer/judge the explorer meets and the colony's ruling Commandant grant him special prestige as a "Westerner," and each hopes to win his support in their struggle over the colony's traditional judicial procedure. The explorer ultimately refuses to support the officer, causing him to put himself in his own execution device. The explorer's experience of the penal colony troubles him greatly, and he leaves in haste.
The new Commandant, and other members of the penal colony, view the explorer as a representative of a more "modern" and "progressive" world, while looking at their own traditions as backward.
The explorer does intervene in the affairs of the colony, but could not have avoided doing so, since even remaining silent about the officer's procedure would have doomed it.