Yumiko Hoshino, a young adventurer from the eastern country of Jinsoku, has spent three years searching for her missing older brother. Her journey leads her to the world's largest guild, where she becomes entangled in a mystery far greater than she imagined. Haunted by ethereal voices, she is eventually guided to Lukas Adler, a former member of her brother's guild party. Together, Yumiko and Lukas begin to unravel the mystery behind the voices that brought them together. As they face the shadows of their pasts and the challenges ahead, they embark on an adventure that will test their willpower and determine the fate of the world.