Yoshitaka, who was about to leave his marriage and his wife, is poisoned by arsenic-laced coffee and dies. His wife, Ayane, is the logical suspect -except that she was hundreds of miles away when he was murdered. The lead detective, Tokyo Police Detective Kusanagi, is immediately smitten with her and refuses to believe that she could have had anything to do with the crime. His assistant, Kaoru Utsumi, however, is convinced Ayane is guilty.