Irene Adler, American opera singer and the one woman who outsmarted Sherlock Holmes, finds herself a widow at thirty-two, wealthy but emotionally broken. At the same time, Sherlock Holmes finds himself unable to return to England after faking his death at Reichenbach Falls and is drawn into an investigation of two men with designs on a woman they call Miss A, who is none other than Irene Adler herself. The Detective and The Woman throw their lot in together to uncover a dangerous plot with implications that stretch across the Atlantic. In the process, they meet legendary inventor Thomas Edison and experience life in Florida at the turn of the 20th century.

The mysterious death of Irene Adler's bees leads to a consultation with Sherlock Holmes and the discovery of a sinister connection to a case many years in the past. When this threat imperils the safety of everyone the detective holds dear, he and The Woman are forced to use every ounce of their ingenuity to save their friends.

Irene Adler is enjoying a quiet, undisturbed life in Sussex when the mysterious disappearance of a local farmer named James Phillimore throws her world into turmoil and forces her to enlist the aid of her friend and former enemy Sherlock Holmes. Irritated by his flatmate John Watson's romantic inclinations, Holmes journeys to Fulworth to assist The Woman in her investigation. Along the way, the two uncover the darkness, intrigue, scandal, and unexpected loyalty that lie at the heart of a seemingly-innocent village and a case filled with diabolical deception.