In a terrifying future world, four girls must depend on each other if they want to survive. Now that best friends Louisa, Rosie, Evelyn, and Maddie know the truth — or at least the danger they're in — the girls have run away from their "safe" country retreat. But life is riskier than ever, and Rosie still doesn't know who she can trust. Rosie's survival skills are top-notch. But how well can she keep her own secrets?