Death Descends on Saturn Villa — M.R.C. Kasasian

Gower Street, London: 1883.
March Middleton is the niece of London's greatest (and most curmudgeonly) private detective, Sidney Grice. March has just discovered a wealthy long-lost relative she never knew she had. When this newest family member meets with a horrible death, March is in the frame for murder and only Sidney Grice can prove her innocence.

Grice agrees to investigate (for his usual fee) but warns that he is not entirely convinced of her innocence. If he were in her position, he might have been tempted. But the more he uncovers, the more all the clues point to Grice himself...