Anna nearly dies at age four from the deadly Cacao virus. She survives, thanks to a mysterious red-headed poisonous krait. The medical community is excited because there is currently no known cure for the virus, but Anna's krait, which she thinks a Red Angel sent to take her to heaven and her dead parents, is not the answer. She and her Red Angel have a symbiotic relationship that provides remission but not a cure. If she is ever separated from the krait, the virus will become active, and she will die within days.