The Quartering Duke, a notorious serial killer with over a hundred victims, has unleashed chaos in the country with his heinous acts. To put an end to his bloodshed, the "Detective Alliance," consisting of the world's top detectives, has gathered to discover and subdue him.

However, in a series of unexpected events, an ambitious but insignificant detective named Wato Hojo gets entangled in their operations. He joins the Detective Alliance on the mysterious Morgue Island to investigate the Quartering Duke, only to make the terrifying discovery that their target is hiding among them! Can these detectives prove their innocence and reveal the identity of the Quartering Duke before the case goes cold?

The Mark of Fourteen: Team up with 13 other detectives, each with their own unique abilities, tools, and personalities. Explore key locations around Morgue Island and engage in choice-based dialogues to gather useful clues for each case.

A Study in Shadow: Conduct investigations on an interactive crime scene map. Use your "Denouement" ability to absorb critical information, predict the future, and gather evidence while piecing together the truth behind each murder.

The Island of Fear: As the secret headquarters of the Detective Alliance, Morgue Island hosts many mysterious and dangerous areas. Explore a variety of vibrant locations, including a labyrinth, research center, and the Alliance's mansion for clues about the Quartering Duke.