A fanfiction could be about a character who discovers that skipping stones was an ancient art lost in the Supernatural world. As they start to learn and practice it, they unearth secrets about their own past and the history of the hunters.
The main themes in Supernatural often include family and sacrifice. In a skipping stones fanfiction, the act of skipping stones could be a family tradition among hunters. When a character skips stones, it could be a way to remember a lost family member, thus tying into the family theme. And if a character has to sacrifice their chance to skip stones (maybe it has some power - granting properties) to save another, it would incorporate sacrifice.
She might be heartbroken. Hermione is a strong - willed character, but being cheated on would surely shatter her. She could initially be in disbelief, given her trust in Ron. Then, she might become angry and start to distance herself from Ron, focusing more on her own studies or other relationships, like her friendship with Sirius.
One possible story could be that in these 10 months, Ron and Hermione are on a mission together. They face many challenges that test their relationship. Maybe they have to deal with a dark wizard threat and in the process, their bond deepens as they rely on each other's strengths.
Hermione, on the other hand, could become more vulnerable yet also stronger. She has always been strong - willed, but this experience could break her down initially. However, as she copes with the miscarriage, she might find new depths to her strength. She could become more in tune with her emotions and learn to lean on Ron more, which is a change from her usually independent self. This new dynamic between them would reshape their characters as they support and grow with each other through this difficult time.
Charlie might be a character who has known Hermione for a long time, maybe through some other connections in the wizarding world. He sees Hermione as someone in need of protection from Ron, whether Ron is acting out of his own accord or is being influenced by external forces. In relation to Ron, he is the one who stands against Ron's actions towards Hermione.
Hermione would likely be very angry at first. She is a strong - willed character and being kidnapped would go against all her principles of freedom and rights. She would probably try to reason with Ron immediately, using her logical arguments to make him see how wrong his actions are.
Well, Ron could have developed a more patient side to his personality. He's had experiences that taught him to be more understanding. Hermione may have become more laid - back. Maybe she realized that she was too uptight before. When they reunite, Ron's new - found patience helps him deal with Hermione's still - somewhat - controlling nature. And Hermione's more laid - back attitude allows Ron to feel more at ease around her. It's an interesting dynamic shift that can make for great storytelling in fanfiction.
I'm not a big fan of such dark fanfictions, but you could try looking on fanfiction.net. They have a large collection of Harry Potter fanfictions, and you might be able to find one with that plot there.
Perhaps in the fanfiction, Ron's jealousy gets the better of him. He might be jealous of Hermione's success or her friendships with other characters like Harry or some of her academic peers. His jealousy could manifest in ways that make Hermione feel suffocated or unappreciated, causing her to end the relationship. Also, Ron may have some habits that Hermione can't tolerate anymore. For example, his slacking off on certain responsibilities or not taking things as seriously as she does.