This episode works pretty well, but one can dismantle in a few seconds with a bit of thought. When that Connecticut Yankee of Mark Twain's went back, Twain ignored the implications of the whole scientific world. Here we must recognize those things. An astronaut finds himself 200 years in the future, encountering an Earth that will likely die soon. Some well-meaning biologist has done something that has caused this horror. Because the astronaut has gone through a time warp, he makes the trip back, accompanied by a hideous future denizen, a man of great moral character and sadness over the results of humanities stupidity. As they find their way back to the present, the astronaut disappears because of time factors. The creature, however, manages to land the ship and sets about trying to kill the person responsible for the great calamity. At the very least, to stop his wife from producing an offspring. He barges in using a convenient form of hypnosis, shielding his ugliness, and tries to destroy the relationship and stop the wedding. The story ends about the only way it could because of the messing with causality. It's a really depressing conclusion. I'm still waiting to see if someone can really produce something satisfying when it comes to time travel.
Review of The Man Who Was Never Born
