The Knights of the Cornerstone

Preliminary description from Blaylock:

"The book is set on the Colorado River, in the desert near where Arizona/Nevada/California come together. There’s a century-old town there on the river called New Cyprus that’s unincorporated, operated by the Knights of the Cornerstone, who appear to be a service organization. Strange things, however, happen in the area of their “temple.” My character is… summoned… to visit his aging aunt and uncle, his uncle being the Grand Master. My man is transporting, at his uncle’s request, what he believes to be the spirit veil of a long-dead aunt, a veil which contains her ghost. Then all sorts of things happen. ."