In just half a year, the bodies of six unknown men floated to the island in the Inland Sea of Seto. This series of mysterious events triggered widespread speculation, and the island was named "Dead Island" as a terrible name. The handsome and talented scientist and private investigator Hiroshi Tamagi heard the legend of Dead Island from the editor Miyuki Ogawa (Hiroase Alice), which aroused his infinite curiosity and set off for the Inland Sea immediately. After some investigation, Imperial hand washing quickly determined that all six bodies were from Fushan City, Hiroshima Prefecture. Of course, the anonymous body did not stop there, and soon the body of a foreign woman who died violently was found, and another man and woman were detained in a waterfall. Several cases are inextricably linked, and Imperial hand washing even dates back to the major events that took place at the turn of the warring States and Edo periods. The truth contained in the intricate clues gradually surfaced.