RUNAWAYS by Lorraine Pinelli Brown

In The Runaways, the witch sickness has reached the people of Ballard, Rachel's safehaven, and has whipped the people's minds into high unpredictability and unlogic. All the world seems to be crumbling around her. John Andrew, Rachel's husband, reunites with her after five long years of relentless searching, but, like his beloved, he is no longer thoroughly himself. He has taken on the persona of a great and angry Lord, charging into Ballardtown, pistol drawn just as the young Midwife, Rebecca, and Lydia, Rachel's closest friend and conspirator in her wild Physician's charade, are pushed to the hanging tree. Unknown to all, an Objibwe Shaman, named Blue Coyote, has come down from the Great Lakes to see the English whites he has heard of. He has been spying for many days. The Sorcerer has come to this place to know these kind—and by his judgment, all will live or all will die.
 
In this series:
The Puppets of Low Magic
The Runaways
Blood Moon