The term 'MOVIE's Storyline' can be summarized as the PLOT of a MOVIE. The PLOT is the sequence of events that make up the story of a MOVIE, and it is usually the main focus of the MOVIE. It is the narrative arc that drives the story forward and keeps the audience engaged. The crossword solution for this term is 'PLOT', which is a four-letter word. PLOT is the foundation of any MOVIE, and it is what makes a MOVIE memorable and engaging.