Mary Russell is well used to dark secrets-her own, and those of her famous partner and husband, Sherlock Holmes. Trust is a thing slowly given, but over the course of a decade together, the two have forged an indissoluble bond. But what of the other person Mary Russell has opened her heart to, that third member of the Holmes household: Mrs Hudson? Russell has come to love-and trust-the long-time housekeeper like the mother she lost so long ago. Mrs Hudson, once the most long-suffering landlady in all of London, followed Holmes into his Sussex retirement back in 1903. Surely she had good reasons for that? Russell has never questioned why...until a man comes to the door one morning, claiming to be Mrs Hudson's son. What Samuel Hudson tells Russell shatters her childish faith. It cannot possibly be true, yet she believes him. She also believes his threats: both the gun in his hand, and the knowledge he holds.In a devastating instant of choice, Russell declares her loyalty and love, and everything changes.Blood on the floor, a token on the mantelpiece, the smell of gunshot in the air: all point directly at Clara Hudson-or rather, at Clarissa, the woman she was before Baker Street.The key to Russell's sacrifice lies in Mrs Hudson's past, and to uncover the crime, a frantic Sherlock Holmes must put aside his anguish and push deep into his housekeeper's secrets, to a time before her disguise was assumed, before her crimes were buried away. There is death here, and murder, and trust betrayed.And nothing will ever be the same.