What is the origin of the idiom "lose the plot" and when to use it?

The idiom "lose the plot" likely originates from the world of literature and storytelling, specifically in reference to the plot of a novel, play, or movie. To "lose the plot" means to become confused or disoriented regarding the narrative of a story. This phrase is often used to express that someone has become confused, disoriented, or has lost their focus or understanding of a situation or task.