A tragic love story between a prostitute and a young trainee monk.

Yoshinari Bessho, the feudal lord of Tanba Province, is a collector of butterflies and has his concubines tattooed with butterflies as well. One day while hunting, Yoshinari sees Gennosuke Akizuki's beautiful wife, Okoto. He kidnaps her, tattoos a butterfly on her shoulder and takes her for his own. Feeling shame for what has happened, Okoto throws herself into a well and commits suicide. She then returns as a ruthless ghost that seeks revenge against Yoshinari and his retainers. Whenever the ghost appears, mysterious butterflies always fly around her...

17 year old Saki lives in a run-down shack with her mom, who survives by pushing a food cart from dawn to dusk. Saki has dropped out of school, and when she's not helping her mother selling noodles in the streets, she's playing flesh-games with boyfriend Sotoo. In her spare time, the girl also entertains a truck driver named Ataru. She believes her promiscuity is a trait inherited from her mom. Determined to improve her lot in life, Saki decides to stop seeing the two guys.