On a stormy summer day in the 1970s the Aosawas, owners of a prominent local hospital, host a large birthday party in their villa on the Sea of Japan. The occasion turns into tragedy when 17 people die from cyanide in their drinks. The only surviving links to what might have happened are a cryptic verse that could be the killer’s, and the physician’s bewitching blind daughter, Hisako, the only family member spared death. The youth who emerges as the prime suspect commits suicide that October, effectively sealing his guilt while consigning his motives to mystery.

Inspector Teru is convinced that Hisako had a role in the crime, as are many in the town, including the author of a bestselling book about the murders written a decade after the incident. The truth is revealed through a skilful juggling of testimony by different voices: family members, witnesses and neighbors, police investigators and of course the mesmerising Hisako herself.