B-Story
The secondary storyline, often a relationship arc, that carries the story's thematic message.
Last updatedIn screenwriting, the B-story is the secondary storyline that typically begins early in Act Two and carries the story's deeper thematic meaning. It is most commonly a relationship arc, whether romantic, platonic, or mentorship, that helps the protagonist learn the lesson they need to overcome the main conflict. The B-story provides emotional depth that the action-driven A-story cannot.
In Finding Nemo, the A-story is Marlin searching for Nemo, but the B-story is Marlin's relationship with Dory, which teaches him to let go and trust. In The Dark Knight, the B-story between Batman and Harvey Dent explores the film's theme of whether Gotham deserves a hero who plays by the rules.
The B-story is distinct from a generic subplot because it specifically serves the protagonist's internal arc. While subplots can involve any secondary storyline, the B-story is the one most intimately connected to the protagonist's growth. It often provides the key insight or emotional shift that enables the protagonist to succeed (or fail meaningfully) at the climax.