Rising action is the section of a story that leads toward its climax. Because of the increased tension as a book's central conflict (or conflicts) become clear, the rising action is often what keeps you turning the pages.
Not every book or movie plot works exactly the same way, but most of them start with some basic exposition that introduces the characters and setting, followed by rising action that pulls the reader or viewer toward the story's most emotional and interesting moment — its climax. The rising action does a lot of the story's work, as it includes the most vital parts of the plot, making thrillers thrilling and page-turners engrossing.