World famous, award winning, always touring. That's the life for A Cappella group Pentatonix, but with this young group growing up, sparks fly. Mitch Grassi and Scott Hoying get married, and two years later are ready to, sort of, settle down. So they adopt little Karlie, a three year old with a traumatizing life. "She'll never get to be a normal kid." Is her life story. So what will happen when they let this little one in their lives? Past horrors for the three of them reappear, and they just hope that they can keep their little family together.