The Madness of Mercury is the first in the A Zodiac Mystery series by Connie di Marco, who also writes the Soup Lovers Mysteries as Connie Archer.  This series is set in San Francisco, with the protagonist, Julia Bonatti, being an astrologer, who is targeted by a religious cult leader at the same time she is being asked for help by an elderly client in fear of her caretaker.

The plot unfolds as Julia deals with the cult disrupting  her life and business and the businesses of other occult shop owners and  business people in the community.  Julia is also trying to ease the mind of Evandra, who feels she is in danger due to the terms of a trust and will.  Julia uses her star charts and investigative skills to follow up on all the threats and uncover what is really happening.  Who is the charismatic cult leader and what does he really want?  Is Evandra really in danger?  If so, from who?  Should Dorothy let Richard back in her life?

Great start to a cozy series!  I look forward to reading the next one.  Just one note, it would be helpful to have an appendix explaining the horoscope system and terms.