Perhaps a story where Renesmee gets into some trouble with a group of vampires who don't accept her existence, and Jacob has to fight to protect her. This could involve some intense battles and also show the depth of Jacob's love for Renesmee as he risks his life for her.
One interesting plot idea could be Jacob teaching Renesmee about the werewolf culture. Since she's part vampire and part human, she might be curious about the werewolves. Jacob could show her how they communicate within the pack, their traditions, and how they protect their territory. This would create a unique bond between them as she learns more about his world.
Perhaps they kiss in secret at first. Then Renesmee starts to have strange powers emerging because of the strong emotions from their relationship. Jacob is worried about how this will affect Renesmee and tries to find a way to control or understand these new powers. It could lead to a journey of discovery for both of them.
One idea could be that Jacob and Renesmee, as humans, have to hide their relationship from the vampire community who might not approve. They could go on adventures together, exploring the human world that Renesmee has just discovered. Another plot could involve them facing some sort of human danger, like a natural disaster or a group of bad humans, and having to rely on each other's unique skills to survive. Jacob's werewolf - like instincts might still be there in a more human way, and Renesmee's special abilities could also play a role in protecting them.
One idea could be Jacob and Renesmee going on a journey to discover more about Renesmee's unique abilities. They could encounter other supernatural beings along the way who either help or hinder them.
Well, perhaps the fanfic could focus on how their relationship changes during the pregnancy. Jacob might become even more protective of Renesmee. And they could also be worried about the future of their child, given their special natures. They may seek advice from the older and wiser members of their clans.
One plot idea could be Renesmee and Jacob going on a secret adventure away from the rest of the Cullen family and the werewolf pack. They discover a hidden place in the forest that has some kind of magical or ancient power. Another could be them facing a new threat together that neither the vampires nor the werewolves have encountered before, and they have to use their unique bond to overcome it. A third idea is that Renesmee starts to develop some new abilities that she doesn't understand, and Jacob is the only one she trusts to help her figure them out.
One possible plot could be the challenges they face in their relationship due to the unexpected pregnancy. For example, how they deal with the reactions from their families and friends in the Twilight universe. Another plot might involve the preparations for the new life, like finding a safe place to stay.
A possible plot is that Renesmee gets into trouble with some vampires who don't trust her because of her unique nature. Jacob steps in and tries to make peace between them. He uses his relationship with Renesmee and his standing among the Quileute to negotiate a truce, all while their bond grows stronger in the face of the conflict.
One possible plot could be the challenges they face as a young couple expecting a baby. Maybe they struggle with telling their families, especially considering the unique nature of their relationship in the fanfiction world. Another could be how they prepare for the baby, like finding a place to live and getting things ready for the new arrival.
A more complex plot could involve Renesmee being in danger from a new threat in the vampire - human world. Charlie, despite being a human, decides to take matters into his own hands. He teams up with some of the Cullen family members in a way that no one expected. This story could explore the relationships between humans and vampires in a different light, with Renesmee and Charlie at the center of it all.