Booke of the Hidden

In this urban fantasy series debut, the discovery of a mysterious book in her tea shop immerses a woman in a world of demons, witches, and murder.
To get a fresh start away from a bad relationship, Kylie Strange moves across the country to open a shop in the seemingly quiet town of Moody Bog in rural Maine. During renovations on Strange Herbs & Teas, she discovers a peculiar and ancient codex, The Booke of the Hidden, bricked into the wall. Every small town has its legends and unusual histories, and this artifact sends Kylie right into the center of Moody Bog's biggest secret.
While puzzling over the tome's oddly blank pages, Kylie gets an unexpected visitor—Erasmus Dark, an inscrutable stranger who claims to be a demon, knows she has the book, and warns her that she has opened a portal to the netherworld. Kylie brushes off this nonsense, until a series of bizarre murders put her, the newcomer, at the center. With the help of the demon and a coven of witches she befriends while dodging the handsome but sharp-eyed sheriff, Kylie hunts for a killer—that might not be human.

"Westerson creates an utterly believable history of witches, demons, and magic for her claustrophobic New England village including a heroine with enough spark, smarts, and stubbornness to keep both the bad guys and the deliciously dangerous love-interest on their toes."—Kat Richardson, author of the Greywalker series