南宋时汉水流域河盗猖獗，朝廷为剿灭匪患派出“横江军”精英章盖出任特使，稽查河上大案。查案中与退役军人莫客偶遇，二人在误会中建立友谊。恰逢莫客亲人女孩玉佩被河盗掳走，二人携手救出玉佩和被拐儿童，将河盗正法，还一方平安。
Based on the book by the same name, the film tells the inspiring story of a 12-year-old boy, who, separated from his family by a fast moving storm, must fight to stay alive during his nine-day adventure lost in the backwoods of Maine.
