Barry S Brown 
Mrs. Hudson and the Irish Invincibles [PDF ebook] 

Moira Keegan is certain that someone is trying to kill her father. She tries to recruit Sherlock Holmes to save his life, but all at 221B Street are certain that there is no basis for Moira’s fears. When, a short time later, they read of the man’s death in a sleazy waterfront inn, the members of London’s premier consulting detective agency have a new client and a singular purpose. Their investigation will place them at odds with Scotland Yard’s Special Branch, Irish revolutionaries, religious zealots, and even staff of the London Times. Only Lestrade remains an ally, and he dare only participate covertly with his frequent colleagues. Before all can be brought right, the Baker Street trio will have to call on the assistance of Charles Stewart Parnell, leader of the Irish Parliamentary Party, and his mistress Katharine O’Shea.