Rescue: a Derrick King Novel, Book 4 in Bloomington, MN

In Discovery, book 3, Derrick King reunited with his sister, Miriam, and their friend, Rebekah Ford. Miriam and Rebekah escaped Pacific Edge, leaving no small crisis in their wake. Rebekah followed Miriam but had second thoughts because she left her sister, Anna, behind. After finding Derrick and returning to Potterville, they learned Anna had followed them the night they escaped and is now hunted by a force known only as Prime.
Derrick and Miriam promise to rescue Anna.
They don't know where Anna is but know the rescue is dangerous.
They just don't understand how dangerous it is.