B Story / Subplot

The secondary thread — often a relationship — that carries the theme while the A story carries the plot.

The B story runs alongside the main plot at lower intensity: the romance inside the thriller, the family strain inside the heist. In Snyder's model it's where the theme actually lives — the B-story character says the thing the hero needs to hear.

Subplots earn their pages by intersecting: the best B stories collide with the A story at the worst possible moment and complicate the climax.