Let's get the BUY link out of the way, shall we? This book is by the fabulous Laura Bickle - you may have read her other books, Embers or Sparks, or possibly Dark Oracle or Rogue Oracle.
From Amazon's description of the book:
"Katie is on the verge of her Rumspringa, the time in Amish life when teenagers can get a taste of the real world. But the real world comes to her in this dystopian tale with a philosophical bent. Rumors of massive unrest on the “Outside” abound. Something murderous is out there. Amish elders make a rule: No one goes outside, and no outsiders come in. But when Katie finds a gravely injured young man, she can’t leave him to die. She smuggles him into her family’s barn—at what cost to her community? The suspense of this vividly told, truly horrific thriller will keep the pages turning."
The writing is gorgeous, even more so when the scenes are intense and chilling. I love this book and this heroine. I hope you do, too.