An incantation of cats
(Book)

Series numeration from www.goodreads.com.

"When two new clients seek Becca's professional services, the fledgling witch detective is overjoyed. Finally, she can use her skills to help her magical community. But as the young witch finds the new cases intertwining, things grow more complicated. Becca's three cats - the ones with the real power - can smell something is wrong with these clients. But not even Clara, the calico, knows what to do when a man ends up dead and a powerful and poisonous root appears - and disappears - in the case. To make matters worse, Clara and her littermates are feuding - and she can't tell them about an unsettling interaction she's had with one of the client's sisters. Is it possible that some humans may have the same powers as the magical felines? What does that mean for Clara's beloved Becca - and for the potent poison that has already taken one person's life? In this second Witch Cats of Cambridge mystery, Clara and her sisters must learn to work together if they are to save the person they all love" --,Amazon.com