It's a little difficult to tell about the second book in a trilogy since there is a part before and a part after. Beverly Lewis' series "Seasons of Grace" tells the story of Grace Byler's Amish family in "The Secret", "The Missing", and "The Telling".
With the exception of the Rumschpringe (an adolescent running-around time), an Amish person's life generally runs in an orderly way. Yet, Grace's mother, Lettie, has suddenly run away from home to parts only guessed at. Lettie's parents have a fear that they know where she is and why Lettie left her family, but they aren't telling. This leaves Lettie's husband and children confused and feeling abandoned.
In "The Missing", Grace wanders slightly afield in a local search for her mother at the same time as a handsome young man tries to court her while helping around her father's farm.
The book ends with Grace and her "Englisher" friend Heather driving off to Ohio in Heather's fancy car.
The third book in the series is on my bookshelf awaiting an opportune time. To be continued...