With Morning Comes Mistfall
"With Morning Comes Mistfall" is a science fiction story by American author George R. R. Martin, published by Analog magazine in May 1973. It was the first story by Martin to be nominated for Hugo Award and Nebula Award. It was included in published in his 2003 anthology Dreamsongs: A RRetrospective (Volume I).
Plot summary 
The story takes place on a barely habitable planet (Wraithworld) with unusual weather conditions. Each morning in a wonderful phenomenon the mist comes down from the mountains escaping the daylight, revealing the beauty of the planet. This phenomenon is called Mistfall.
The planet is home to only few people mostly because it is believed that its mist-covered valleys are occupied by wraiths, claimed to have killed a number of humans. Wraiths are also the main things that attract visitors to the place. The only establishment on the planet is a hotel (Castle Cloud) mounted on top of one of the mountains. The castle is visited by Wraith-Hunters, people looking for a thrill, for something unknown, unexplored.
The novel tells a story of the expedition set out to find the proof of Wraith existence or once and for all establish that they are nothing more than a myth. The owner of the only establishment on the planet fears either answer. He clearly doesn't want to have the mystery of Wraiths uncovered.
The main theme of the story is a clash between two views of the world, one very logical, pragmatic, physical, and the other one romantic and spiritual. It shows that not all mysteries need to be uncovered, not all secrets revealed, that unknown is not always bad, that it keeps people searching, asking questions, coming back. What is known for certain, is often taken for granted and then loses attraction.