The Ones Who Walk Away From Omelas is a short piece of Philosophical Science Fiction following a visitor to Omelas, a beautiful city with a secret:
The city's constant state of serenity and splendor requires that a single unfortunate child be kept in perpetual filth, darkness, and misery.
Once citizens are old enough to know the truth, most, though initially shocked and disgusted, ultimately acquiesce to this one injustice that secures the happiness of the rest of the city. However, some citizens, young and old, walk away from the city after seeing the child.