Seventeen-year-old New Yorker Carson Smith is resigned to spending his summer in Billings, Montana, helping his mom take care of his father, a dying alcoholic he doesn't really know. Then he meets Aisha Stinson, a beautiful girl who has run away from her difficult family, and Pastor John Logan, who's long held a secret regarding Carson's grandfather, who disappeared without warning or explanation thirty years before. Together, Carson and Aisha embark on an epic road trip to find the answers that might save Carson's dad, restore his fragmented family, and discover the "Porcupine of Truth" in all of their lives.