"The Emperor's Trail" is a fictional story that takes place in the cities of Kurashiki and Takahashi, where a monster called Gashadokuro has started to kill people. Detective Yamabushi is the only one with the skills to track down the murderer and follow the trail of clues. The story is based on a fictional myth of the battle of Mizushima and follows Detective Yamabushi as he works to solve the mystery and bring the perpetrator to justice.