Agnes Campbell's Hat

After an old hat and a storm leave modern girl, Tessa Hensen, trapped in a past century and living in the hobbit-like house of a homesteader's family on the Oklahoma Territory prairie, she is forced to accept help from an infuriating farm boy to get back to her real life.
Tessa lives as twelve-year-old Agnes Campbell while Judd Howard helps her solve the mystery of the hat. Sparks fly between the two of them as his old world and her new world collide. He does everything possible to get rid of her; she longs to escape him and his grumpy, old-fashioned ideas about everything.
Gradually, her unwanted family's everyday struggle for survival draws Tessa into the past. When Elizabeth—a Kiowa Indian girl—befriends her, the hardships finally seem bearable.
The two girls face a terrifying encounter with an outlaw and an old Christian man sacrifices his life for theirs, forcing Tessa to ask herself the question: Does she really want to leave behind the past…and Judd?