It’s barely a story at all in the plot sense, mostly a description of a genuinely happy city delivered by a narrator who keeps interrupting herself to argue with you about whether you actually believe her happiness is possible, and then, a few pages in, the reveal, all of it runs on one suffering child locked in a basement, known to everyone, sanctioned by everyone, the price of everyone else’s joy. That’s the entire mechanism. It shouldn’t work as well as it does in so few pages.
I read this originally for a philosophy class covering utilitarianism, and I think that context sells the story short, it’s not an illustration of a thought experiment, it’s an argument with the thought experiment, sharper than most of the philosophers who cite it. The ending is the part that actually earns the title, a small number of citizens learn about the child and simply leave, no protest, no rescue, just walking out of the city into somewhere the narrator admits she can’t describe because it doesn’t exist yet. I’ve seen that ending called both hopeful and bleak depending who you ask, and I think it’s deliberately both.
What surprised me rereading it recently is how much the prose itself does the ethical work, the narrator’s constant self-interruption, insisting you picture it right, refusing to let you flatten the city into simple utopia, is doing exactly what good moral philosophy should do and mostly doesn’t bother trying. Short enough to read in twenty minutes. Long enough to still be sitting with me a week later, uneasy in exactly the way I think Le Guin wanted.