Perhaps Kai kidnaps Elena to force her to help him with something. He might need her doppelganger blood to break a curse on himself or his family. In the process, Elena discovers a side of Kai that she didn't expect, and they form an unlikely alliance against a common enemy that emerges during the ordeal.
One possible plot twist could be that Sakura has been secretly training a new jutsu and uses it to outwit Orochimaru at the last moment. For example, she might have developed a genjutsu that can counter Orochimaru's mind - control techniques. Another twist could be that Naruto and Sasuke arrive just in time, but instead of a straightforward rescue, they find that Sakura has made a deal with Orochimaru in order to gain some powerful knowledge. This could lead to a rift between her and her teammates.
One possible plot twist could be that the 'Uzumaki' who kidnaps Naruto is actually an impostor. Maybe it's someone with shape - shifting abilities who wants to use Naruto for some dark purpose. For example, they could be trying to extract the Nine - Tails' chakra from Naruto in a more brutal way than the Akatsuki ever planned.
It could be that Fem Sasuke is under some sort of mind - control when she kidnaps Naruto. A powerful enemy, like Orochimaru or a new villain, might have used a jutsu to make her do this. As the story progresses, Naruto would then have to find a way to break the mind - control on Fem Sasuke while also dealing with the situation of being kidnapped.
Well, perhaps the plot could involve Hermione actually getting through to Tom Riddle in some way. Since she's so intelligent and empathetic, she might start to make him question his dark ways while being kidnapped. This could lead to a really interesting internal struggle within Tom. Also, there could be a twist where the kidnapping is part of a much larger plan that involves other dark wizards or witches, and Hermione has to figure out how to not only escape but also stop this bigger conspiracy. Or it could be that Hermione discovers a secret about Tom Riddle's past during her captivity that she can use to her advantage.
Well, one possible plot twist could be that Kohana has a hidden motive that's not as evil as it seems at first. Maybe she's being controlled by a greater force and Naruto realizes this and tries to save her instead of just escaping. Another could be that Kohana is actually from a long - lost clan that has a prophecy related to Naruto, and the 'kidnapping' is a way to start fulfilling that prophecy.
Perhaps a plot twist could be that Elena discovers she's pregnant, but Elijah has lost his memory due to some dark magic. So, she has to deal with the pregnancy on her own while also trying to find a way to restore his memory. This would add a lot of emotional turmoil to the story.
One possible plot twist could be that the pregnancy is part of a prophecy. Maybe there's an ancient prophecy that states a child born from Klaus and Elena will either bring great destruction or be the key to saving the supernatural world. This would add a layer of mystery and danger to the story.
One possible plot twist could be that a long - lost relative of Elena shows up to oppose the marriage. Maybe this relative has some ancient grudge against the family that Elijah is from. Another twist could be that a powerful witch casts a spell on Elijah, making him forget his love for Elena right before the wedding. Then Elena has to go on a quest to break the spell.
Well, one plot twist could be that the father of her baby is not who everyone suspects. Maybe it's a character who has been secretly in love with her all along. Another could be that there are some supernatural elements affecting her pregnancy, like a curse that changes the nature of the baby.
One possible plot twist could be that the pregnancy is part of a magical spell gone wrong. Maybe a witch with a vendetta against either Kol or Elena cast a spell that made Elena pregnant, and now they have to figure out how to reverse it without harming the baby or themselves. Another twist could be that the baby has some sort of special power that attracts all kinds of supernatural threats, forcing Kol and Elena to constantly be on the run and protect their unborn child.