A hook is an engaging element in storytelling designed to capture the audience's attention and spark their curiosity from the very beginning. It can be a striking image, an intriguing question, or a surprising fact that draws people in and makes them want to learn more about the story. A strong hook is essential in various aspects of screenwriting, including short synopses, loglines, pitches, and query letters, as it sets the tone and creates immediate interest in the narrative.