《亨利之书》讲述小男孩亨利为了保护邻居家的小姑娘不被她的父亲所伤，暗自策划了一场谋杀。Sometimes things are not always what they seem, especially in the small suburban town where the Carpenter family lives. Single suburban mother Susan Carpenter works as a waitress at a diner, alongside feisty family friend Sheila. Her younger son Peter is a playful 8-year-old. Taking care of everyone and everything in his own unique way is Susan's older son Henry, age 11. Protector to his adoring younger brother and tireless supporter of his often self-doubting mother - and, through investments, of the family as a whole - Henry blazes through the days like a comet. Susan discovers that the family next door, which includes Henry's kind classmate Christina, has a dangerous secret - and that Henry has devised a surprising plan to help. As his brainstormed rescue plan for Christina takes shape in thrilling ways, Susan finds herself at the center of it.