The Witches of Crannock Dale by Thomas M. Kane

Spies. Witch-hunts. A little girl who asks dangerous questions. Eleven-year-old Mara wants to go on being her pappy’s little girl forever, but when knights of the official church arrest her favorite aunt on trumped-up charges of witchcraft, she leaves her safe childhood world behind. Shocked by adults’ willingness to accept injustice, she runs away from home to rescue her aunt from execution. She finds that respected members of her community are using her aunt as a scapegoat to cover up their own collaboration with foreign agents. As Mara schemes to protect her family from these conspirators, she deduces that they are part of a larger plot which threatens her entire nation, and which her country’s leaders fail to see. That problem is too large for a child to solve, but it will define Mara’s life.