The Three-Act Structure is a storytelling framework that divides a narrative into three distinct parts: Setup, Confrontation, and Resolution. In the first act, the main characters and their world are introduced, along with the central conflict that drives the story. This sets the stage for the journey ahead. In the second act, the characters face challenges and obstacles, leading to rising tension and deeper conflicts. Finally, the third act brings resolution, where the characters confront their challenges, and the story concludes. This structure is commonly used in films, novels, and plays, making it a fundamental tool for writers like William Shakespeare and Christopher Nolan.