Watson recieved a telegram from Holmes.He wanted him to accompony him to solve a murder at Boscombe Valley.
Holmes told Watson that the victim was Charles McCharty , a widower who has a son named James. Charles has been found dead near Boscombe pool. Two witness testified that they saw Charles walking into the wood followed by James who was bearing a gun. Patience Moran , daughter of a gamekeeper says she saw James arguing with his father.
Moran ran home quickly and told his mother what she saw. A few minute later , James rushed to their house seeking help. A gamekeeper and a policeman find Charles McCharthy body.
Moran and the policeman found James gun. James was arrested on charges of murdering his father. But Holmes did not think so because Alice , John Turner's daughter told him that James was a kind boy.
Holmes continued telling Watson about James at his trial. At his trial , he confirmed the testimonies of the witnesses , but he explained that he went to the wood to hunt , not to follow his father. James told the judge about the incident.
At Boscombe pool , he heard a familiar sound. Someone calling "cooee" and he found his father standing near the bushes , suprise to see him.They argued heatedly and James decided to went back home. After that , he heard his father cry out and he found his father lying weakly. He tried to help but his father died in his arm. The judge asked him about the argument but he said it was personal. He also explained that he saw a grey coat on the ground.
Alice met Holmes , Watson and Lestrade at a local hotel. She said that James was innocent because he was too kind to hurt anyone especially his father. She also believe that she was the subject of the argument between James and his father. Holmes asked Alice if he could met her father , but she say that his father's health worsened after the death of Charles.
Holmes met James in prison. Holmes mistakenly surmisesed that James know who killed his father. James told that he had been married. Holmes promised that he will help James.
Holmes told Watson that Alice did not know that James really love her and wanted to marry him but he could not because he had already married a barmaid for Bristol. The next day , Holmes , Watson and Lestrade went to Boscombe pool to find the clues.
Holmes find evidence of the presence of another man beside Charles and James , whom he believe to be a murderer. The stranger is a tall , limping and left-handed man who smoke Indian cigars. But Lestrade is not convinced. At the hotel , Holmes explained to Watson that "cooee" was an Australian cry and "raat" were the last syllables of Ballarat , a place in Australia.
John comes to their room and realizing that Holmes has deduced the crime confess. In his confession , John explained that he was the "Blackjack of Ballarat". John and his gang robbed a gold convoy in which was Charles was the wagon driver. After the robbery , John became rich and he moved to England.
After 20 year , John met Charles again and he threatned to blackmailed him. In response John gave Charles a house and a lot of money. However , Charles asked more money from John. Charles demanded the marriage of James and Alice to get all John's money. Although he likes James , John could not allow Charles eventual control his family's finances through Alice. Eventualy ,John decided to meet Charles secretly at the Boscombe pool. Seeing Charles and James there arguing , John waited until James left and killed Charles. Holmes promised that he will destroy the confession until the freedom of James.
Seven month later , John Turner was dead and Holmes destroyed the letter. James and Alice married and they were happy.