The Inugamis

When tycoon Inugami Sahei passes away, he unexpectedly leaves the family fortune to outsider Tamayo on the condition that she marries one of the Inugami grandsons - Sukekiyo, Suketake, or Suketomo - pitting blood against blood. Soon afterwards, members of the family begin to show up dead, one by one. Detective Kindaichi Kosuke is called in to investigate the murders, and the truth is slowly revealed as he happens upon years of hidden skeletons and a shocking family secret.
~~ Adapted from the novel “Inugamike no Ichizoku” (犬神家の一族) by Yokomizo Seishi (横溝正史).