Comienza este relato cuando Watson recibe un telegrama de Sherlock Holmes, mientras desayuna apaciblemente con la señora Watson. El texto dice: "¿Tiene usted un par de días libres? Acabo de recibir un telegrama del oeste de Inglaterra en relación con la tragedia del valle de Boscombe. Me encantaría llevarle. Tiempo y panorama excelentes. Saldré de Paddington a las 11.15 h." Watson parte con Holmes hacia el valle de Boscombe, una región cerca de Ross, en Herefordshire. A su llegada, el inspector Lestrade de Scotland Yard se encarga de ponerles en antecedentes de lo que, dentro de su miopía habitual, es un caso claro. El joven James ha asesinado a su padre, el granjero McCarthy. Aunque la culpabilidad del joven parece evidente, atendiendo a las súplicas de Alice Turner, hija del millonario John Turner e íntima amiga del joven, por caballerosidad, Lestrade ha solicitado la presencia de Sherlock Holmes. Éste demostrará, una vez más, la ineficacia de los métodos policiales habituales. Gracias a su brillante actuación, saldrá a la luz un sórdido caso de chantaje y venganza, donde el auténtico criminal resultará ser la propia víctima. Lestrade summons Holmes to a community in Herefordshire, where a local landowner has been murdered outdoors. The deceased's estranged son is strongly implicated. Holmes quickly determines that a mysterious third man may be responsible for the crime, unraveling a thread involving a secret criminal past, thwarted love, and blackmail. Sherlock Holmes and Dr Watson take a train to Boscombe Valley, in Herefordshire. En route, Holmes reads the news and briefs Watson on their new case. John Turner, a widower and a major landowner who has a daughter named Alice, lives there with a fellow expatriate from Australia, Charles McCarthy, a widower who has a son named James. Charles has been found dead near Boscombe Pool. It was reported that he was there to meet someone. Two witnesses testify that they saw Charles walking into the woods followed by James, who was carrying a gun. Patience Moran, daughter of a lodgekeeper, says that she saw Charles and James arguing, that, when James raised his hand as if to hit his father, she ran to her mother, and that while she was telling her mother what she saw James rushed to their house seeking help. The Morans followed James back to the Pool, where they found his father dead. James was arrested and charged with murder. Alice Turner believes that James is innocent and has contacted Lestrade, a Scotland Yard detective who in turn has asked Holmes' help.