The Passage by Justin Cronin is the first in a series of three books about a post-apocalyptic Earth. Horror is the genre in question, but Cronin leans far into suspense as well. After a certain Dr. Lear advances his program to build super-soldiers to human testing, he unwittingly sets off a chain of events which end his life and human civilization as it was known. He conducts tests on Tim Fanning, twelve death row convicts, and six-year-old Amy Bellafonte. Each responds in consequential but various ways.
As the protagonist, Amy immediately passes from unknown and normal child to the sole person capable of fighting the destructive effects of the serum on all the adults. The adults become subject to the spread of radiation from the experiment. Some die. And some become "virals" or vampires basically. Others, like Amy's protector, Brad Wolgast, die gradually from radiation poisoning. Regardless of the person in question, however, everyone loses somebody or something important. The world plunges into darkness (literally) and chaos as the original twelve subjects wreak havoc with their superhuman powers on the surviving human population.
Amy's personal transformation, from naive child to savior, is representative of the series' core values. She is deliberately cast as an ordinary person who steps into an extraordinary fate. As the direct result of the adults -- Sister Lacey and Brad Wolgast -- who invest in Amy's mental, emotional, and physical health, she grows into a capable and fierce leader among the survivors. She develops a rare fortitude, one which helps her survive the internal turmoil which delayed aging and the post-apocalypse cause. She directs her attention outward, sharing the love which she received with her immediate neighbors.
