Well, maybe the story could start with Stiles finding out about the baby unexpectedly. For example, an old acquaintance shows up with the baby and reveals that it's his. Then he has to deal with the shock and start learning how to be a father while still keeping it a secret from his friends and family.
One possible plot could be that Stiles is involved in some sort of supernatural event that led to the baby's existence in a very strange way. Maybe there was a spell or some magic that made a baby appear in his life. And he has to figure out how to take care of the baby while also dealing with the mystery behind its appearance. He might be afraid of how his friends, especially those involved in the supernatural world, would react if they found out.
Perhaps in the fanfiction, Stiles had a relationship in the past that he didn't fully disclose. And the girl got pregnant. She decided to keep the baby a secret from Stiles at first, but now circumstances force her to bring the baby into Stiles' life. Stiles then has to balance his normal life, like school or work, with this newfound fatherhood.
It could be an original character created just for this fanfiction. Maybe a girl who Stiles met during a summer vacation and had a brief fling with.
One possible plot could be that Stiles discovers he has a baby unexpectedly. Maybe an old fling left a baby on his doorstep. He then has to learn how to be a father while still dealing with his normal life, like school and his friends. He might struggle at first with things like changing diapers and getting up in the middle of the night, but with the support of his friends, he slowly gets the hang of it.
Well, perhaps the story could be about Sakura trying to hide the existence of her baby from society due to some kind of stigma or danger. Maybe she's a young and unwed mother in a very traditional setting.
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.
In this fanfiction, it might be that the baby has some special powers. Derek with his werewolf abilities and Stiles with his intelligence have to figure out how to raise the baby while also helping it control its powers. They could face challenges from other supernatural beings who either want to use the baby's powers or are afraid of them.
It could be someone from Stiles' past that he had a brief relationship with. Maybe a girl he met during a summer vacation or a girl from another town that he had a fling with and then lost contact with until she shows up with the baby.
Maybe in the fanfiction, the father of the baby is a mystery. Clary has to deal with the speculation and rumors around who the father could be while also taking care of her little one. It could add a lot of drama to the story as she might face accusations or unwanted attention.
His best friend could discover it. Since they are so close, they might notice something different about Stiles that makes them suspect he's actually a girl.
One possible plot could be that Stiles and Derek's relationship has developed over time. Stiles discovers he has a son, perhaps from a past encounter he didn't expect to have consequences. Derek, being a werewolf with a strong sense of family, steps in to help Stiles raise the child. They might face challenges from the supernatural world, like other werewolves or creatures who see the child as a threat or an opportunity. And along the way, their relationship deepens as they bond over the care of the son.
One possible plot could be that Pocahontas and John Smith reunite and start a family. They face the challenges of raising a child in a world where their two cultures collide. The baby could be a symbol of hope for the future, bridging the gap between the Native American and English settlers.