The Red Tower by Mark A. Latham
This Sherlock Holmes novel is very good. Watson is invited to a weekend party by James Crain. Watson learns his friend has fallen under the malign influence of Spiritualists. Watson must uncover the truth when a séance leads to devastating consequences and a feeling of ominous dead descends on the house.
In between his gruff literary pretension and honest workable commitment to the truth, Watson lives in Holmes’ reflected glory. But one way or another the malign intent of the Spiritualists will be exposed, it is a moral imperative.
“Can’t you see what she’s presaging?”
“There are other fanciful tales also, mostly regarding mad ancestors and wronged women.”