Five years after it began, a handful of scattered survivors remain, including Malorie and her two young children. Living in an abandoned house near the river, she has dreamed of fleeing to a place where they might be safe. Now, that the boy and girl are four, it is time to go. But the journey ahead will be terrifying: twenty miles downriver in a rowboat--blindfolded--with nothing to rely on but her wits and the children's trained ears. One wrong choice and they will die. And something is following them. But is it man, animal, or monster?