Kouya, a rookie detective, is walking deep inside the forest. It was two weeks ago, a hand of an unidentified creature washed up on the shore of a river. Hard and thick skin, bristle like an animal, thick fingers and sharp nails, it was not a human's hand. Also, there was a jewel ring on the ring finger.

This mysterious story was featured in a magazine and caught people's attention. Days later, the police found that it was a woman's hand, who had been missing for a month. She went missing when she played golf with her friends nearby. The police confirmed she was attacked by a stray dog, but couldn't explain why the hand looked so differently. They tried to close the case, but her husband wasn't convinced. He didn't want to believe his wife was a monster. He decided to ask a detective to investigate the case, that's why Kouya is now roaming around deep inside the forest.

It is getting dark, but he doesn't know where he is now. Just when he feels dizzy, he hears someone's voice. Is that auditory hallucination? He hears a girl's voice this time. "I've been saved!" But he accidentally falls down a waterfall. When he regains his consciousness, he finds himself lying in the bed. He looks around and finds three girls. "Are you alright?" "Well, did you save me?" "Yes, I and my older sister carried you all the way here." Their mother says to him, "I'm relieved to see you getting well. But you must marry either of my daughters, Sunao or Hiori."

He doesn't know what she means. A mysterious hand bitten off by someone, a small village deep inside the forest, marriage to a miko, Kouya's fate is led to unexpected direction after he meets these two girls...