Kurenai no Tsuki – a visual novel that begins the story of a newly minted detective who went deep into the forest about two weeks ago. Investigators encountered the hand of an unknown creature that ended up on the river bank. An examination showed that the hand had hard and thick skin, stubble instead of hair, thin fingers and sharp nails. On one of the fingers there was a ring with a precious stone.

After some experiments, the police managed to find out that this was the hand of a girl who had gone missing more than a month ago. Friends with whom she had been playing golf called the police and reported a missing person. The police found that the woman had encountered an aggressive stray dog, which subsequently killed her. However, the husband of the deceased is not sure that this happened. No one could explain why the hand was so different from a human one.

The husband did not want to believe that his wife was a monster. He had to turn to a private detective to investigate the mysterious case. The player takes control of the investigator, who set off on a dangerous journey to uncover the secrets of what happened. As the game progresses, the protagonist will encounter paranormal phenomena and unusual creatures many times. Most of the gameplay takes place in dialogues and monologues between characters or in the protagonist's mind.