Secondary storyline running parallel to the main plot — often an emotional subplot featuring supporting characters. Reinforces the film's central theme.
Technical Details
The B-story follows its own curve of tension with setup (pages 12-17), development (pages 45-60), and resolution (pages 85-95) based on the 110-page screenplay standard. It possesses its own plot points, which differ from the A-story but contribute thematically. Classic B-story types include the love story, mentor relationship, or family drama. The subplot features at least two independent characters with separate motivations and a completed character arc.
History & Development
In 1939, screenwriting theorist Syd Field introduced systematic B-story analysis, based on studies of classic Hollywood productions. RKO Pictures established its first story guidelines in 1941, mandating a subplot for all A-productions. Robert McKee, in his 1997 book "Story," refined the modern B-story definition: thematic reinforcement of the main plot through parallel emotional development. Since 2010, streaming series have expanded the concept to C- and D-stories for episode lengths of 45-60 minutes.
Practical Application in Film
In "Casablanca" (1942), the Rick/Ilsa love story forms the B-story to the political A-story concerning the transit papers. "Die Hard" (1988) uses the McClane/Holly marital crisis as an emotional B-story parallel to the action-driven main plot. "The Godfather" (1972) develops Michael Corleone's family foundation as a B-story, contrasting his character transformation with the A-story. The B-story usually begins after the A-story's inciting incident and reaches its climax before the final showdown.
Comparison & Alternatives
The B-story differs from a subplot by its thematic centrality – subplots remain peripheral, while B-stories reinforce the main theme. C-stories exist as tertiary plot threads in more complex narratives, typically with 5-10% screentime. Ensemble films utilize multiple-protagonist structures instead of a classic A/B-story division. Minimalist narrative forms deliberately omit B-stories to achieve narrative focus.