The purpose of a story arc is to ENGAGE the audience's attention and effect a CHANGE. A story arc is needed in every speech, presentation, audio recording, and series episode. For the story to go somewhere, change must occur from the beginning of the speech, to the end of the message, and beyond the spoken words. 'Flat lining a message' occurs when a speaker fails to take the audience on a journey. Story arcs can be from avoidance to acceptance, confusion to understanding, boredom to action, disconnection to support, disappointment to success, etc. The story arc style can be simple, complex, dramatic, or comedic. So remember, the speaker's narrative story arc takes the audience on a journey, which is the foundation of good storytelling.