An auto repairman's daughter questions him about what happened to her aunt during the war, but the father remains reticent. Finally the man opens up, and the girl is able to piece together her aunt's tragic story.

Hiroshi Hamano, a professor at a medical university, is found dead. Going by the results of the autopsy, it appears he committed suicide by jumping off a roof, but going by eyewitness testimony and physical evidence at the scene, Detective Kamei suspects murder. A ticket for a train trip around Japan is found in the professor's pocket. However, nobody then could have known the shocking truth hidden behind the tour the dead man was supposed to attend...