Ribbon in the sky

"Ribbon in the Sky" by Murray Leinster is a science fiction tale where a pilot named Calhoun finds himself stranded on a unique planet, marked by a strange light formation high above. The story explores the effects of mistakes and being alone, especially on groups of people cut off from everyone else. The inhabitants of this planet suffer from a fear of outside illnesses, a problem Calhoun faces head-on when he learns of a young couple trying to break free from the feuding communities they live in. Calhoun becomes part of a journey that tests both his medical skills and ability to handle social issues as he works to help these isolated people overcome their fears, all while thinking about how human errors can affect whole societies and how important it is to be connected to others.