The man is rare who will give his life for what is merely the lesser of two evils. Merrick's decision was even tougher: to save human beings at the expense of humanity, or vice versa?
John Carter, a Confederate veteran of the American Civil War, goes prospecting in Arizona immediately after the war's end. Having struck a rich vein of gold, he runs afoul of the Apaches. While attempting to evade pursuit by hiding in a sacred cave, he is mysteriously transported to Mars, called "Barsoom" by its inhabitants. Carter finds that he has great strength and superhuman agility in this new environment as a result of its lesser gravity.
What is desirable is not always necessary, while that which is necessary may be most undesirable. Perhaps the measure of a man is the ability to tell one from the other. and act on it.
It has been 60 years since the great Red Death wiped out mankind, and the handful of survivors from all walks of life have established their own civilization and their own hierarchy in a savage world. Art, science, and all learning has been lost, and the young descendants of the healthy know nothing of the world that was-nothing but myths and make-believe. The old man is the only one who can convey the wonders of that bygone age, and the horrors of the plague that brought about its end.
A man will always be willing to buy something he wants, and believes in, even if it is impossible, rather than something he believes is impossible. So. sell him what he thinks he wants!