Dr. Mid-Nite lands on Neptune, and spots some sort of a man-built communications system. He is met by several creatures and taken to meet Hydara, ruler of the subterranean people and made a slave. Just then, a person runs in and states that he has caught the dreaded plague that has been killing off his people. Dr. Mid-Nite deduces that they merely have the measles, which he can easily cure. He asks for herbs and makes a solution that the people can absorb through their feet-roots. As a reward, he is given a complete set of books describing their secrets of plant growth and surgical work.

Plot details indexed by the Grand Comics Database (CC BY-SA).