Professor & Mrs. Moriarty tackle a case too ticklish for Sherlock Holmes to handle on his own.

James and Angelina Moriarty are settling into their new marriage and their fashionable new home — or trying to.Then Sherlock Holmes comes to call with a challenging case. He suspects a prominent Harley Street specialist of committing murders for hire, sending patients home from his private hospital with deadly doses or fatal conditions. Holmes wants to investigate, but the doctor's clientele is exclusively female. He needs Angelina's help.

While Moriarty, Holmes, and Watson explore the many ways a doctor can murder patients with impunity, Angelina poses as a nervous woman seeking treatment from their primary suspect. Then half-truths and angry words drive James and Angelina apart, sending her deep into danger. They must find the courage to trust each other as they race the clock to win justice for the murdered women before they become victims themselves.