What the hex
(Book)

"Penny Roundtree wants nothing more than to be a familiar to a witch. She's been a member of the Society of Familiars ever since she was old enough to join the Fam. There's just a small problem-no one's hiring. Witches and warlocks are so long-lived that there are far more familiars available than witches to train them. So when an unorthodox arrangement to apprentice under the table to a forbidden warlock presents itself, she takes it. Willem Sauer is banned from having a familiar due to past transgressions, thereby limiting his magic-casting abilities. Unfortunately for the surly, Prussian warlock, he has no choice but to work with enthusiastic Penny as a familiar. They immediately clash like dried roan horsehair and honeycomb gathered by moonlight (it's a terrible spell combination, ask anyone). Casting spells has delightful perks Penny never could have dreamed of, but also greater dangers. Someone is targeting Penny. Willem and Penny must work together to catch their enemy, and if their ploy requires a little kissing on the side, who is to question the rules of magic?"--