Story: this would be a broad, organizing category. Each User could have many Stories (and I suppose a Story could have multiple Users). This would allow me to have multiple projects underway at once.
Scene: I'm not sure how Scene would differ from Card, exactly, but I'm thinking along the lines of: Scene represents an event in the Story, with associated Characters, props, a Place (Location?), and a sequence of Events.
I'd like to see these new models: