Detective Kyosuke Kozu's Murder Reasoning 5

The film centers on newspaper reporter Kenzo, who inadvertently becomes embroiled in a murder case after a chance encounter with a mysterious woman named Emi. When Kenzo drops by his girlfriend's home, he discovers a bloodied knife in a suitcase that has mysteriously replaced his own. This leads him to seek the help of Kyosuke, a university professor and renowned detective, who is also Nobuko's older brother.

As the plot unfolds, Kyosuke investigates Emi's family background, revealing troubling dynamics within the Kayama family. Emi and her sister Yuri, both daughters from a previous marriage, return home after years of separation, setting the stage for a complex investigation. The film offers an intriguing blend of family drama and mystery, making it a notable entry in the Detective Kyosuke Kozu series.