"To further the plot" means to advance or develop the storyline or events in a book, movie, or play. It refers to actions, dialogue, or events that contribute to the overall progress or resolution of the narrative. Full definition
They observed 12 further plots on the mainland for comparison. (news.mongabay.com)
This is the point at which the movie really kicks into gear, so I will leave further plot points for you to see for yourself in the movie. (tomorrowland-movie.com)
Some of the face to camera interruptions throughout the film are quite intrusive, especially when they don't actually further the plot. (hoopla.nu)