Her Irish father having died in a construction accident, Kate O'Connell and her mother are left to struggle alone in the Minneapolis of 1906.
Seeing her mother struggle to support them and sensing her loneliness, Kate seeks help in finding her a new husband. But when her mother marries a Swedish man from northwest Wisconsin who is a widower with two sons and one daughter of his own, Kate becomes very concerned.
As conflict builds with Anders, the stepbrother her age, Kate sees puzzling things happen around the farm. When danger threatens, will she and Anders learn to work together? Who is the stranger who appears then disappears? Will they solve the mystery and become a true family?