The Masterful Mr. Montague (Casebook of Barnaby Adair 2)

Montague has devoted his life to managing the wealth of London’s elite, but at a huge cost: a family of his own. Then the enticing Miss Violet Matcham seeks his help, and in the puzzle she presents him, he finds an intriguing new challenge professionally . . . and personally.
Violet, devoted lady-companion to the aging Lady Halstead, turns to Montague to reassure her ladyship that her affairs are in order. But the famous Montague is not at all what she’d expected—this man is compelling, decisive, supportive, and strong—everything Violet needs in a champion, a position to which Montague rapidly lays claim.
But then Lady Halstead is murdered and Violet and Montague, aided by Barnaby Adair, Inspector Stokes, Penelope, and Griselda, race to expose a cunning and cold-blooded killer who stalks closer and closer. Will Montague and Violet learn the shocking truth too late to seize their chance at enduring love?