Mrs Jeffries On The Ball by Emily Brightwell
This charming series of Victorian murder mysteries features mild-mannered Inspector Witherspoon of Scotland Yard and, more importantly, Mrs Jeffries, his housekeeper. A policeman's widow herself, her quick wits allow her to nudge the Inspector in the right direction to solve the crime.
Murder strikes at a Jubilee Ball in Queen Victoria's honour, which is also attended by Inspector Witherspoon and Mrs. Jeffries. The victim was a widely disliked member of the Hyde Park Literary Circle, where investigations into the crime open old wounds and reignite petty grievances ... 'Aghast, the inspector's jaw dropped even farther. He couldn't believe this. "Lady Cannonberry, have you any idea what you're saying?"'