I'm working on a novel that is told from a single narrator in third person. A number of subplots detail the stories of secondary characters.
My problem: From their point of view, I could easily write full-fledged scenes about the secondary characters and their respective stories. However, I would very much prefer to stick to my single narrator and have him, somehow, observe the story of the secondary characters.
Which brings me to my questions: How do I write a good, dynamic scene, when the narrator is a mere observer? Do I need to go to the trouble and give him a separate goal that is somehow related to the "real goal" of the scene - the goal of the secondary character? Or can the secondary character's goal support an entire scene?
Example: Meet Hannah. Hannah wants to be a dancer and works very hard to get accepted at the country's best dance ensemble. She's the narrator of the story, the main plot evolves around her struggle to get accepted. A subplot is the story of Hannah's mother, who's had a mild problem with alcohol for quite some time. She falls in love with a senior dancer in Hannah's group and decides to stop drinking. This has nothing to do with Hannah. Yet, for me, it could be a crucial element of the story. When I write the story from Hannah's point of view, how would I go about writing her mother's resurrection - the scene in which she proves that she can give up drinking for good? How can I make the scene about Hannah's mother, while it still is part of Hannah's story, too?