The Adventure of Charles Augustus Milverton

The Adventure of Charles Augustus Milverton by Arthur Conan Doyle Audiobook is one of the 56 Sherlock Holmes short stories written by Sir Arthur Conan Doyle. It was originally published in Collier's in the United States on 26 March 1904, and in The Strand Magazine in the United Kingdom in April 1904. It is one of 13 stories in the cycle collected as The Return of Sherlock Holmes (1905).

Plot:
Holmes is hired by the débutante Lady Eva Blackwell to retrieve compromising letters from a blackmailer: Milverton, who causes Holmes more revulsion than any of the 50-odd murderers in his career. Milverton is "the king of blackmailers". He demands £7,000 (equivalent to £838,304 in 2021) for the letters, which if given to third parties would cause a scandal that would end Lady Eva's marriage engagement. Holmes offers £2,000, all Lady Eva can pay, but Milverton insists on £7,000.

It is worth £7,000 to him, he explains, to make an example of Lady Eva; it is in his long-term interest to ensure that his future blackmail victims would be more "open to reason" and pay him what he wants, knowing he will destroy them if they do not. Holmes resolves to recover the letters by whatever means necessary, as Milverton has placed himself outside the bounds of morality.

Holmes visits Milverton's Hampstead house, disguised as a plumber, in order to learn the plan of the house and Milverton's daily routine. He cultivates the acquaintance of Milverton's housemaid and even becomes engaged to marry her. This rather shocks Watson, but Holmes assures him that he has a hated rival who will step in when the plumber disappears. Holmes has learned where Milverton keeps his blackmail papers (a safe in his study), and plans to burgle Milverton's house that night. Watson comes along.

They break into the study, but just as Holmes opens the safe, Milverton enters the study, even though he should be in bed asleep. Holmes and Watson hide behind a curtain, while Milverton has a midnight meeting with a supposed maidservant offering to sell letters that would compromise her mistress.

Milverton's death, 1904 illustration by Sidney Paget
The woman is actually one of Milverton's former victims, whose broken-hearted husband died when she wouldn't pay Milverton and he revealed her secret. Now she avenges her husband by shooting Milverton to death, then stamps on his face.