Sahei Inugami, the founder of the Inugami Conglomerate, a financial giant in the Shinshu region, has just passed away. The clout wielding decedent left a will which ironic formulation hints at a bitter family feud. The ensuing battle over the vast legacy triggers a series of strange, cruel murders. The talented detective assigned to the case, Kosuke Kindaichi, soons finds himself delving into a labyrinthine family lineage. But a truth beyond imagination still awaits him.