The story could also involve Hermione using her magical knowledge to help Tom control his powers. Since Tom is a powerful wizard from a young age, he might have difficulty handling his magic properly. Hermione, being a brilliant witch, could guide him. This could lead to a unique bond between them, where Tom respects Hermione for her abilities and Hermione sees the potential for good in Tom.
Hermione would likely approach Tom's dark past with a great deal of research. She'd probably dig into the history of Voldemort's early years to understand what led him down that path in the first place. By knowing the root causes, she could try to prevent the same things from happening to Tom. For example, if she found out that loneliness and a sense of being an outcast were factors, she'd make sure Tom had a strong support system at Hogwarts.
One possible plot twist could be that Tom Riddle's dark tendencies start to resurface despite Hermione's positive influence. Maybe he begins to secretly manipulate those around him at Hogwarts while still maintaining a facade of being a reformed child. This could lead to a rift between Hermione and some of her friends who suspect Tom but don't understand why Hermione is so trusting.
If Hermione adopts Tom Riddle, it could potentially prevent the rise of Voldemort. This would mean a much more peaceful wizarding world. There would be no First or Second Wizarding Wars, and countless lives would be saved. Families like the Potters and the Weasleys would not have to endure the pain and loss they suffered in the original timeline.
She would face the challenge of dealing with Tom's own nature. Even as a baby, he might have some of the traits that later led to his dark side. Hermione would have to find ways to nurture his good side and suppress the bad. Also, she has her own life and studies. Balancing taking care of a baby and her own development would be difficult.
One way this could be somewhat plausible is through a time - travel or alternate universe scenario. Maybe in a world where the rules of magic are bent, Tom Riddle's dark past is rewritten, and he somehow meets Hermione in a different context. However, it goes against the canon nature of their characters. Tom Riddle is a dark wizard with very different values from Hermione. In the original story, they exist in different eras. But in fanfiction, creative liberties can be taken to explore how their personalities might interact in such a situation.
I really liked 'My Adopted Son, Tom Riddle'. This fanfiction has a unique take on the idea. The reader not only adopts Tom but also tries to shield him from the dark influences at Hogwarts. It has some great plot twists and the writing style is very immersive.
In a fanfiction where Hermione is Tom Riddle's daughter, the storyline would be turned upside down. The prophecy about Harry and Voldemort might need to be re - evaluated as Hermione's connection to Voldemort could potentially change the balance of power. Her relationships with other characters would be complex. For example, Dumbledore might have had a different plan all along if he knew about Hermione's true parentage. The Death Eaters could also try to recruit her, seeing her as a way to get closer to Voldemort. This would create a whole new set of conflicts and challenges for Hermione, Harry, and Ron, and would lead the story in a completely different direction from the original.
It would change the future of the wizarding world a great deal. Hermione is a smart and kind - hearted witch. With her as Tom's mother figure, she would likely encourage his academic pursuits in a positive way. He might grow up to be a great wizard who uses his powers for good instead of evil, thus changing the whole power dynamic in the wizarding world.
Redemption is a common theme. Since Tom Riddle later becomes Voldemort, many fanfictions with an oc adopting him focus on whether he can be redeemed through the love and care of the oc. Another theme is the power of family. The oc often tries to create a family - like environment for Tom, which is something he lacks in the original story.
Perhaps in the fanfiction, Harry adopts Tom Riddle when he's still a young boy at the orphanage. Harry then uses his own experiences of growing up without parents to bond with Tom. He teaches Tom about magic in a different way than Dumbledore did, focusing on the positive aspects of magic for good. This could lead to Tom not becoming the evil Voldemort we know.