In November 1998, a double murder takes place at the newly built Ogawa apartment complex in central Mifune City. The killer, Tomoe Enjou, flees in a state of panic. To his surprise, the police do not pursue him, and the incident receives no media coverage. After Shiki Ryougi protects Tomoe from a group of thugs, she lets him hide out at her place. A few days later, Tomoe is horrified to find that his mother is still alive, even though he is certain he killed her.
Meanwhile, Mikiya Kokutou looks into a tip that his associate Touko Aozaki receives concerning the murder at the unusual apartment complex. As Mikiya uncovers more details about the incident, he becomes especially interested in Tomoe. Deciding to investigate him further, Mikiya soon learns the disturbing truth behind the ominous Ogawa complex.
The fifth entry in the Kara no Kyoukai film series, Mujun Rasen blends an intricately constructed mystery with established themes and characters to create a dark, thought-provoking story.