A scruffy detective investigates the murders of three sisters on a small Japanese island in 1946.

Kôsuke Kindaichi, a somewhat peculiar private detective, visits a remote town. He meets a police detective and they start to investigate an old unsolved murder. Then some murders happen. Kindaichi…

When a tycoon passes away, he unexpectedly leaves the family fortune to outsider Tamayo on the condition that she marries one of the grandsons, pitting blood against blood.