Your hero and heroine haven’t seen each other for a decade. A lot has changed. This is an unplanned reunion. They are both on the same train. There’s an altercation between your heroine and someone and your hero shows up out of the blue. How does she feel? Why is there an altercation, what’s going on? What does your hero do when he sees her? Why are they both on the train, where are they going? Why did they break up? So many questions to have fun with! I see this as a contemporary, but honestly it could be a time travel, a western, or suspense. Where does your imagination take you with this one?