Kikuzo Hayashiya

Inugami Sahei, who built up the wealth of the Inugami Clan, passes away, leaving a will with Furudate, his legal adviser, for his daughters Matsuko, Takeko and Umeko, all of whom have different mothers, and for their sons, as well as for Nonomiya Tamayo, the granddaughter of a person to whom Sahei feels heavily indebted. The will states that all his assets are inherited by Tamayo alone, on the condition that she marries one of the sons of the daughters. Furudate's assistant learns the content of the will, and seeks advice from Kindaichi Kosuke, a private detective, as he senses the air of unease. Shortly afterwards, murders start to occur one after another in the clan.

Naomi is a university student who is leaving for the US to study in a week; Shuichi is a washed-up gumshoe who's hired by Naomi's father to bodygard his daughter until she leaves. Shuichi finds the job annoying and wants to quit. But he also has a screwed-up ex and alimony to pay. Things go from bad to worse when Naomi and Shuichi stumble upon a murder which might involve the yakuza. They decide to find out who committed the murder but God knows what it will lead to.