The way I brainstorm sometimes is to go into different genres.
Drama… the protagonist just left a relationship (not of her own choosing) and is trying to fill her life with something she thought she was missing but didn’t realize she never had before (someone devoted to her as much as she was devoted to him.)
Thriller… A serial killer is following her. Killing someone after she leaves a city, and it’s someone she had contact with at some point during her visit.
Horror… the protagonist is using the “story” as a cover to track an incubus, who killed someone close to her. It plunges her into a dark world.
Sci-Fi… the protagonist is traveling through time. Visiting different eras to find “the right one.”