The Second Storyline
In screenwriting structure, a film’s narrative is typically broken down into at least two interconnected plotlines. The A Story is the main plot; it is the external, action-oriented journey of the protagonist. It’s about winning the race, stopping the villain, or finding the treasure. The B Story is a secondary, often more intimate and emotional, storyline that runs concurrently. This subplot usually involves a different set of characters and focuses on relationships, providing a contrast in tone and pacing to the main plot.
B Story: Thematic Resonance
The most critical function of the B Story is to carry the thematic weight of the film. While the A Story is about what the protagonist does, the B Story is about what the protagonist learns. The characters and conflicts within the B Story are where the film’s central message or theme is debated, explored, and ultimately proven. Blake Snyder famously referred to the B Story as the ‘love story,’ which doesn’t necessarily mean it must be romantic. It can be about the ‘love’ between a mentor and student, two friends, or a parent and child. It is through the relationship in the B Story that the protagonist is challenged and forced to grow internally.
Weaving the Stories Together
A well-structured screenplay seamlessly integrates the A and B stories. They are not two entirely separate narratives but are causally and thematically linked. The B story is typically introduced sometime after the A story is established, often around the beginning of the second act. Throughout the middle of the film, the narrative will cut back and forth between the two plotlines.
The magic happens when the two stories converge. The emotional or intellectual lesson that the protagonist learns in the B Story becomes the key to solving the problem of the A Story. For instance, in Die Hard, the A Story is John McClane fighting terrorists in a skyscraper. The B Story is his strained relationship with his wife, Holly, and his conversations with Sergeant Al Powell. By learning to be vulnerable and admit his faults in the B Story (with Al), he gains the emotional clarity and drive he needs to ultimately succeed in the A Story (saving Holly and defeating Hans Gruber). The two plots merge in the climax, where the protagonist’s internal growth finally allows them to conquer their external foe.