Well, a plot could revolve around Emma's pregnancy powers. Since she has magic, perhaps her pregnancy enhances it in unexpected ways. Hook could be both amazed and a bit worried as he tries to support her. They could also go on a journey to find a special midwife or healer who can understand the unique nature of Emma's pregnancy because of her magic.
A possible plot is that they discover that their unborn child has a special destiny. This leads them to seek out ancient prophecies or wise beings in different realms. Along the way, they have to protect Emma and the baby from various threats. There could be a sub - plot where Hook's pirate crew has mixed reactions to the news of the pregnancy, some being supportive and others fearing it will change the dynamics of their group.
One idea could be that they face challenges in their relationship while preparing for the baby. Maybe Hook is worried about being a good father because of his past. Another could be that Emma's magic has an unexpected reaction during her pregnancy, like protecting the baby in a magical way. And a third idea is that they discover a prophecy related to their unborn child which forces them to go on an adventure to protect their family.
Perhaps they are in the middle of a new adventure when Emma realizes she's pregnant. This could add a whole new layer of tension as they not only have to deal with the external threats but also ensure the safety of the baby. They could seek help from their friends in Storybrooke, who have mixed reactions to the news.
Emma's character could become more in tune with her emotions. Pregnancy often brings out a range of feelings, and she could use this time to better understand herself. Hook could develop a stronger sense of loyalty not just to Emma, but to the future family they are creating. He may also become more involved in the community around them, as he realizes the importance of a stable environment for their child. This would be a significant shift from his more solitary pirate past.
In another scenario, both Captain Hook and Emma Swan are held for ransom by a new and powerful villain in their world. They have to work together, using their combined skills and the power of their relationship, to escape from captivity. This could involve Hook using his pirate wiles and Emma using her magic. They might also find unexpected allies along the way who help them in their quest to avoid paying the ransom and defeat the villain.
There could be a fanfiction where their baby is the key to saving the Enchanted Forest from a new dark curse. In this story, the baby has a special connection to an ancient magic that only it can unlock.
Adventure is also a big theme. They are often on some sort of quest or journey together. For example, they might be searching for a magical artifact while also dealing with their feelings for each other. And there's also the theme of trust. Since they come from different sides, learning to trust each other is a crucial part of many fanfics.
One common theme is redemption. Captain Hook often has a past full of misdeeds, and in these fanfics, his relationship with Emma Swan can be a part of his journey towards redemption. For example, in many stories, he tries to change for her.
Well, a plot could involve Emma getting lost in Neverland and Peter Pan being the only one who can guide her back to her world. Along the way, they start to understand each other's motives and dreams better. Maybe Peter shows Emma the hidden wonders of Neverland that no one else has seen, and in return, Emma teaches Peter about the concept of true love and family from her world.
Hook might become more protective and less reckless. His focus could shift from his own adventures to safeguarding Emma and the baby. Emma, on the other hand, could become more in touch with her softer side. She has always been strong and independent, but now she has to rely on others more.
One great fanfic is 'The Pirate's Heart'. It delves into a romantic relationship between Captain Hook and Emma Swan in a very engaging way. The story has a lot of adventure elements combined with their growing feelings for each other.