Arrow Pointing Nowhere

In this seventh entry of the Henry Gamadge series, the bibliophile detective receives a cryptic, urgent letter from a stranger named Mr. Fenway, hinting at a hidden crime within his wealthy, claustrophobic household. But by the time Gamadge arrives at the Fenway estate, the man is already dead from a fall that the police have ruled an accident. Unconvinced, Gamadge investigates the gloomy mansion and its tightly knit circle of heirs. His only lead is a singular clue left behind by the victim: a reference to an "arrow pointing nowhere," which Gamadge must decipher to expose a murderer before they strike again.