Isadora Klein was a celebrated beauty and adventuress who resided in London. Though Isadora was of Spanish ancestry, her family had been prominent in the Pernambuco region of western Brazil for several generations. She was an aggressive social climber, and used her beauty and charm to seduce men who could benefit her standing. She married a wealthy and elderly German sugar baron named Klein, who died shortly afterwards, leaving her to inherit his vast fortune.

Following her husband's death Mrs Klein took a string of lovers, among them Douglas Maberley, a British attaché in Italy. However, when Isadora broke off the relationship because of Douglas' lack of wealth, her lover flew into a jealous rage. He wrote a scathing novel starring a thinly-veiled Isadora, which he intended to publish in order to ruin her reputation. His unexpected death by pneumonia in Rome halted his plans, and the manuscript was sent to his mother, Mary, in England.

Isadora, who at the time was engaged to the Duke of Lomond, a man nearly half her age, was worried the document would be found and reveal her scandalous past, thus ruining the marriage and her attempts to rise in society. She therefore hired Barney and Susan Stockdale to help her recover the manuscript. Though Sherlock Holmes was called in by Mary Maberley after some suspicious incidents, the Stockdales managed to steal the book from the house. When Holmes and Watson arrived at Isadora's house to recover it shortly after, to Holmes' anger they found she had already burned it. However, after hearing her story Holmes decided to let her off lightly, only insisting that she pay for a trip around the world for Mrs Maberley.

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