"Kent Montana and the Reasonably Invisible Man" is Lionel Fenn's 6th novel, and the second book in the Kent Montana series.
In this book, Kent returns to his hometown in Scotland to wrap up family issues (namely, that his mother is trying to have him killed so that she can sell off the barony and live the rest of her life in luxury) and instead stumbles into a horrific misadventure of fog, innocent flower girls, cops disguised as hookers, and nearly invisible madmen fulfilling their lifelong dreams of satanic wonder on the moors of Scotland.