A discovery is a passage from ignorance to knowledge. It causes a change that arouses a person’s feelings and stimulates a change in attitude. It motivates a person to make a decision. In Guillermo del Toro’s film, El laberinto del fauno (Pan’s Labyrinth), dreamy ten-year-old Ofelia (Ivana Baquero) moves to Navarra with her delicate, pregnant mother to become acquainted with her new stepfather. Enchanted with fairy tales, Ofelia discovers an overgrown labyrinth behind the mill, and there she discovers an ancient faun who claims to know her true identity and her secret destiny. So, Ofelia’s key discovery sets the story into motion.

A decision is a commitment to take action. Jean Paul Sartre says we are the sum of our decisions, our choices. Decisions are of two sorts, expedient or ethical. Expedient decisions deal with how to do something; ethical decisions concern whether or not to do something. In the long history of narrative writing, Dante and many great authors considered moral choice as the most significant indicator of a person’s deep character. At the climax of Francois Girard’s film Le violon rouge (The Red Violin), Charles Morritz (Samuel L. Jackson) has the assignment to verify that the violin to be auctioned is genuine. After meticulous evaluation, he muses to himself, “What do you do when the thing you most wanted, so perfect, just comes?” His internal reply is the decision to steal the red violin.

A genuinely useful cinematic moment always drives the action forward, increases the tension, or penetrates characters more deeply.

A deed means actually doing something. A character carries out a decision by taking action. In Casablanca, Ilsa (Ingrid Bergman) confronts Rick (Humphrey Bogart), demanding travel papers crucial for her husband’s escape from the Nazis. Rick decides to help him, and leads her to think she will stay behind when her husband leaves. At the last moment, Rick’s deed is making Ilsa get on the plane to Lisbon with her husband. So moments of change — accidents, discoveries, decisions, and deeds — are the materials of a film’s through-line of action. Any one of the four types of moments, or a combination of them, can function as a cinematic moment, a plot point. A genuinely useful cinematic moment always drives the action forward, increases the tension, or penetrates characters more deeply. Inevitably, by witnessing and psychologically joining in cinematic moments, the empathic intensity of viewers’ involvement surges. Functional cinematic moments contain character change and so enliven the structure of action.