A man's body was found by the river, with strangulation marks on the neck of the body, apparently homicide. But with the face mutilated and the fingerprints burnt, it is difficult to establish the identity. After careful investigation, the police identified the deceased as the unemployed Shinji Togashi. Kaoru Uchikai, a female police officer at Kaizuka North Police Station, investigates.
Utsumi visits Shinji's ex-wife Yasuko Hanaoka. Jingzi used to be a wine escort girl, but now she works in a lunch room, raising her daughter who is in middle school by herself. After the divorce, Yasuko moved several times to avoid the entangled Shinji. Although there is a motive for the killing, Yasukiko claims that Shinji has not been seen at all recently, and her alibi is impeccable. Utsumi stumbles upon Yasuko's neighbor, Tetsuya Ishigami, who, like Yukawa Gaku, is a graduate of Teikoku University.
When discussing the case with Yukawa, Uikai mentioned Shishen. It turned out that Yukawa and Shishen were classmates back then. Although they were different majors, they could talk very well and cherished each other. Yukawa, who has always regarded himself very highly, praised Ishigami as a "true genius". Yukawa went to visit an old friend who now teaches math in middle school. However, during the contact, Yukawa found the suspicious point of the case. He believed that Shishen was closely related to the murder.
Detective Galileo challenges the lies, blind spots, and psychological confrontations set by the genius mathematician
.
