D and Spider have always been best friends, and they are further united in their shared grief: they both lost siblings in a horrific plane crash two years earlier. A chance sighting of a beloved cuddly toy in a photograph of the only survivor raises D's hopes all over again that somehow her sister survived. She and Spider and their friend, Min, set off on a road trip to the mountainside site of that terrible crash. Ariel has lived on the mountain all her life. She and her extended family are looked down upon by neighboring townsfolk and she has learned to live by her wits, trusting few people outside of her isolated, survivalist community. A terrifying attack sends her down the mountain for help; on her way, she comes upon the three girls — a chance encounter that will have far-reaching consequences for them all.