Perhaps the baby's existence causes a rift in the wizarding world. Some might view it as an abomination due to the age and past relationship between Hermione and Severus. This could lead to Hermione and Severus having to fight not only for their baby's safety but also for their right to be a family in a world full of prejudice.
A great plot twist could be that younger Snape actually has some knowledge of Hermione's time - traveling. Maybe he's been having strange dreams about the future and when he meets Hermione, he realizes she's part of it. This would completely change the power dynamic between them.
One possible plot twist could be that they face unexpected magical difficulties. For example, a spell gone wrong might temporarily affect their chances of having a baby. Maybe a dark magic remnant in their house, left over from their previous battles, starts to interfere with the natural process. Another twist could be that they discover a long - lost family curse that might be passed on to their potential child. This could lead them on a journey to find a cure before they actually conceive.
Maybe the story could be about Hermione trying to protect the baby from dark forces in the wizarding world while keeping its existence a secret. She might have to face challenges alone without the support of her friends at first.
One possible plot could be Severus saving baby Draco from a dangerous situation. Maybe there's a dark wizard targeting the Malfoy family and Severus steps in to protect Draco. This could start a special connection between them.
One idea could be that Severus and Hermione have to protect their baby from dark forces. Maybe there are some old enemies of Severus who target the baby to get revenge. Another plot could be the baby having some unique magical abilities that they need to figure out how to handle and train.
In this fanfiction, Severus might adopt Harry to protect him from the dark forces that are still lurking around. He would use his knowledge of the dark arts and potions to keep Harry safe. He could also introduce Harry to a different side of the wizarding world, one that is more about academic study and self - discovery. For example, he may encourage Harry to study advanced potions at a very young age, which would give Harry an edge in his future magical education.
One possible plot twist could be that Snape's secret family has a hidden magical ability that is crucial to the wizarding world. Maybe his family has the power to reverse dark magic spells, and this is something Voldemort has been searching for all along.
Maybe in a time - travel fanfiction. Hermione travels back in time and ends up in Snape's student days. She tries to change some events for the better, and in the process, she gets to know a younger Snape. Their interactions are initially rocky but gradually turn into something more, leading to a kiss. This would be a very different take on their relationship, as it involves a different time period and different versions of themselves.
It could be that the dream is a premonition of some sort. Severus and Hermione start to notice similarities between the events in the dream and things that are starting to happen in the real world. They then try to use the knowledge from the dream to prevent a disaster from occurring. This would involve them relying on each other's skills and knowledge, and growing closer as a result.
A plot twist could be that Hermione is initially oblivious to Sirius' feelings. She's so focused on her studies and the fight against Voldemort that she doesn't notice the signs. But then, one day, she accidentally stumbles upon a letter Sirius was writing about his feelings for her. This throws her into a state of confusion as she never expected such a thing from him.