The Keepers of the Flame (Fire-Us, #02)

After a virus destroys most of the world's adult population, a group of children are delighted to discover a colony of adult survivors in a Florida shopping mall but soon find that they are not as friendly as they appear. They have found others. Five years after a deadly plague killed all the Grown-ups, the world's population has nearly vanished. But a group of children have survived and forged a new family, a new life, and together traveled up the coast of Florida, looking for answers. To their shock, they've found a group of adults, the only Grown-ups they've seen for years, living in an abandoned shopping mall. It's a world the travelers had almost forgotten -- cupcakes, clean clothes, adults to depend on. But something is terribly wrong. The family must find the truth before it's too late.