There could be a moral dilemma in the story. What if the kidnapper demands something unethical in exchange for the child? Castle and Beckett would have to decide how far they are willing to go to save their child. This could test their relationship and their values. But in the end, they would find a way to outsmart the kidnapper and get their child back safely.
In this kind of fanfiction scenario, the story could be filled with intense emotions. Castle and Beckett would surely be devastated. They would immediately start using their detective skills and connections to search for their child. They might start by retracing their steps, thinking about any enemies they've made during their investigations. Maybe they'd discover a clue in an unexpected place, like a toy left at the scene that has some hidden message or marking on it.
One possible scenario in this fanfic could be that Castle and Beckett race against time to find the kidnapped child. They might start by interviewing the family and friends of the child, looking for any leads. Maybe they discover that the kidnapper left a cryptic message that only Castle's writer - brain can decipher.
In this fanfiction, the baby boy could be the center of a family drama. Maybe Castle's ex - wife shows up, claiming she has some rights to the baby. This causes a rift between Castle and Beckett as they deal with the legal and emotional turmoil. However, in the end, they come together stronger than ever, with their baby boy being the glue that holds their family together.
Another plot twist could be that the child wasn't really kidnapped but was hidden away by a family member for some strange reason. And as Castle and Beckett dig deeper, they find themselves caught in a web of family secrets and lies that has more to do with protecting the child from a greater danger that they are not yet aware of.
One possibility is that they would face some challenges right after getting married. For example, they might have to deal with combining their two very different lifestyles. Castle is used to his flamboyant and sometimes chaotic writer life, while Beckett has a more structured detective routine. But through communication and love, they would find a way to make it work.
Another thing that could occur is that Castle decides to confront Beckett about what he saw. He could be really straightforward and ask her what's going on between her and Vaughn. This could lead to an argument or a really honest conversation about their relationship.
One possibility is that Castle has booked the hotel for a romantic getaway by himself, and seeing Beckett there completely throws him off. Beckett could be there for a much more serious reason, like following a lead on a dangerous criminal. Castle may start to worry about Beckett's safety and decides to stay close to her. As they interact more within the hotel, they might realize how much they've missed each other's company, and this chance meeting could be the start of something new between them, whether it's a new level of friendship or a re - awakening of their romantic feelings.
A fanfiction could show Peter being kidnapped by a criminal mastermind who wants to use him as leverage against Spider - Man in the future. Peter, as a child, would have to find a way to escape and also figure out how to stop this person from ever coming after him again. It could involve him making new friends among other kidnapped kids who help him in his escape plan.
In a fanfic like this, there could be a lot of emotional turmoil. Beckett and Castle might start to realize how much they actually rely on each other. When they are pretending to be separated, they could find that they miss the little things about each other. For instance, Castle might miss how Beckett always has a smart comeback during their banter, and Beckett might miss Castle's goofy sense of humor. This could lead to some internal conflict for them as they try to maintain the facade while also dealing with their growing feelings for each other during this 'pretend' separation.
Well, it could be that they meet at a summer camp. Beckett is the shy girl who loves to read mystery books in the corner, and Castle is the adventurous boy always getting into little pranks. They might team up to solve a small mystery at the camp, like who stole the counselor's whistle. This initial meeting could plant the seeds for their future relationship as crime - solving partners.