Kasagi Kozo (Sorimachi Takashi), a city assembly member and also the nephew of the mayor, Tayama Yotaro (Issei Ogata), receives a call from his mother about his uncle’s death. The very diligent mayor had suddenly disappeared while on official business. A few days later, his dead body is discovered at a hot spring resort. The mayor has been absent from the assembly for six days without prior notice. At a regular session at the Yokogawa City Hall, jeers about the mayor fly back and forth and it gets chaotic inside. The mayor’s secretary, Yazaki, is hounded. Yazaki has been wondering about something the mayor had abruptly said to him while observing a classic concert. “I wish to skip tomorrow’s session because I suddenly recalled something I have to do.” Furthermore, he had called the hot spring resort he was headed to “Shimagawa Onsen”, which made Yazaki suspect that it was not his first time going to that town. With the help of the mayor’s housekeeper, Tezuka Sumiko (Baisho Mitsuko), Kasagi who doubts that his strait-laced uncle would have excused himself from work for a private matter, cleans up the belongings in his room after his death. That is when Kasagi finds a diary and learns from its contents that his uncle was besotted with a woman called Fujishima Yoshiko (Kimura Tae)! Is there a connection between the details in the diary and his uncle’s disappearance?