Kuon is a horror game set in Heian period (12th century) in Japan. You control three protagonists in the game. The story revolves around a man named Doman, an exorcist who was summoned by one of the noblemen to investigate a cursed manor. His daughter Utsuki is out to search for him when he doesn't return, and her sister is charmed by demons inhabiting a mysterious castle, turning into a demon herself. A young girl named Sakuya, Doman's disciple, also ventures into the depths of the demonic world, to prove herself worthy of her master. Once the player completes Utsuki's and Sakuya's scenarios, they unlocks the third scenario where they experiences the story from the point of view of Doman himself.

The game is a mixture of third-person action and puzzle-solving. As in all survival horror games, your means of defense are limited and scarce. Unlike most games of the kind, physical attacks with weapons are not your only way to defend yourself against hordes of undead creatures. You can also learn and cast spells in the game, and even summon creatures (wolves, spiders, etc.) to fight at your side.