A really interesting plot twist might be that the pregnancy is a key part of a prophecy. Killian and Emma then have to protect the unborn child from various villains who want to use the baby for their own evil purposes. They might have to go into hiding, and along the way, they learn more about each other and their relationship deepens even further.
Perhaps a plot twist could be that Killian is not the father as they initially thought. There was some sort of mix - up or magic involved. Or, the pregnancy could progress at an extremely accelerated rate, and they have to quickly adapt to becoming parents much sooner than expected. This could put a strain on their relationship as they struggle to deal with all the new responsibilities.
In this fanfiction, the plot might revolve around the idea that Killian and Emma are in a world full of magic and danger. When they learn they're having a baby, they have to be extra careful. They might seek the help of their magical friends to ensure the baby's safety during the pregnancy. As the due date approaches, they face a final battle against an evil force that wants to harm their unborn child, and they triumph just in time for the baby to be born healthy.
Another plot twist could be related to the pregnancy itself. What if Sakura's pregnancy was not a natural one but rather the result of some kind of experiment or curse? This could lead to a whole adventure where she has to find a way to break the curse and save her unborn child. She might have to team up with unlikely allies and face powerful enemies in the process.
One possible plot could be that Killian is sent to find teen Emma by some magical force. He finds her and at first, she is very distrustful of him. But as time passes, they start to understand each other. Killian tells her stories about her future self (without giving away too much) and helps her gain confidence. This fanfiction could explore their relationship in a new light, different from their relationship when she is an adult. It could also show how Killian's presence in teen Emma's life could shape her into the person she becomes as an adult in the show.
Well, perhaps Killian could be a stranger who stumbles upon baby Emma. He might be instantly charmed by her innocence. Maybe he has some sort of premonition that she will grow up to be an important person in his life. He could then decide to protect her from any harm in the area, starting a connection that would later develop into a more complex relationship as Emma grows up.
In the fanfiction, it might be that Killian is magically bound to help child Emma find something important, like a lost family heirloom or a key to a magical place. As they journey together, they form an unlikely bond. Killian teaches her some skills, and Emma, in her innocent and curious way, makes Killian see things from a different perspective. Their interactions could be filled with humor, as well as moments of emotional growth for both characters.
One possible ending could be that they fall deeply in love. After going through all the trials and tribulations of getting to know each other, they realize that they are perfect for each other. They build a life together, perhaps starting a family or achieving their individual dreams while supporting each other.
One possible plot twist could be that the pregnancy is not a normal one. Maybe it's part of some alien experiment or a time - related anomaly. For example, the baby could have special powers that are both a blessing and a danger. Another twist could be that the Doctor has to make a difficult choice between saving Amy and the unborn child in a life - threatening situation.
One possible plot twist could be that Caroline initially tries to keep it a secret from Klaus. She might be afraid of how he'll react or what it means for their complicated relationship. But then, circumstances force her to tell him, like a threat from an enemy who somehow finds out about the pregnancy.
One possible plot twist could be that Hancock has to hide her pregnancy from the outside world for the safety of Luffy and their unborn child. Maybe there are enemies who would target them if they knew. Another could be that Luffy has some strange reaction to the news of becoming a father, like initially being really confused but then growing into the role in an unexpected way.
One possible plot twist could be that the pregnancy is not a normal one. Maybe there are some special powers or abilities that the baby inherits which causes all kinds of chaos and challenges. For example, the baby could have the power to manipulate time like Alice, but it's out of control in the womb and affects the flow of time around them.