Well, perhaps a plot twist could be that Percy's friends think he's been kidnapped by someone else entirely. So they're looking in all the wrong places while Khione has him hidden away. Or, it could be that Khione kidnaps Percy but then realizes she's made a huge mistake because Percy has some sort of connection to a force that can destroy her. So she has to figure out a way to either let him go or use him to her advantage in a different way. Also, what if Percy is able to communicate with the elements in Khione's domain and he uses that to his advantage to escape or gain the upper hand?
A really interesting plot twist could be that Khione kidnaps Percy as part of a deal with the gods. However, the gods have their own hidden agendas. Maybe they want Percy to be in a vulnerable position so that he can learn some important lesson. Another plot twist might be that Khione's lair where she's keeping Percy is actually a portal to another dimension. Percy has to navigate this new and strange world to find a way back home. And yet another could be that when Khione kidnaps Percy, she accidentally kidnaps one of Percy's friends as well who has a power that can counteract Khione's, which she doesn't know about until it's too late.
One possible plot twist could be that Bumblebee has a hidden power that he discovers while in captivity. For example, he might be able to communicate with an ancient Cybertronian force that helps him break free. Another could be that Megatron has a secret reason for kidnapping Bumblebee that has to do with an old prophecy. Maybe Bumblebee is the key to unlocking a great power that Megatron wants for himself. A third plot twist might be that Bumblebee's friends think he's been kidnapped, but in reality he went with Megatron willingly to spy on him, only to find himself in a real bind when Megatron discovers his true intentions.
Well, a really interesting plot twist could be that Pitch kidnaps Jack, but then realizes he has kidnapped the wrong 'Jack'. This could lead to a whole series of comical or tense situations as he tries to figure out what to do. Or perhaps when Pitch kidnaps Jack, Jack's friends don't immediately realize it's Pitch. They suspect someone else at first, which causes a lot of confusion in their search for Jack. Also, it could be that Pitch kidnaps Jack into a dream world where the rules are completely different, and Jack has to adapt quickly to escape.
Percy would likely be both angry and calculating. He'd be angry because he's been kidnapped, but he'd also start thinking about how he can use his powers and skills to get out of the situation. He might try to reason with Khione if he thinks it could buy him some time to plan an escape. He'd also be looking for any weaknesses in Khione's defenses or in her personality that he could exploit.
A third plot twist could involve a character we least expect coming to Harry's rescue. Perhaps a Slytherin student who has been secretly against Voldemort all along. This student could have some inside knowledge about Voldemort's lair and manages to free Harry, leading to a change in the dynamic between the houses at Hogwarts.
Perhaps Percy kidnaps Annabeth because he has been misinformed about her. He might believe she has done something terrible, like betrayed the demigods or the gods themselves. As the story unfolds, he discovers the truth, that she has been framed, and then they have to work together to clear her name and stop the real wrongdoers.
Well, a great plot twist could be that Percy is turned into a vampire but he was actually part of an ancient prophecy in the vampire world. As he struggles to adapt to his new life, he finds out that there are vampire hunters who are after him not just because he's a vampire, but because they believe he will bring about a great change in the vampire - human balance. Also, his transformation could be different from other vampires. Instead of craving blood right away, he has a strange attraction to something else, like the essence of magic, which is very un - vampire - like and causes confusion among the vampire clans.
A plot could involve Khione being banished from her icy realm for some reason. Percy takes it upon himself to help her. Along the way, they have to deal with various obstacles, including other mythological beings who are against Khione. Their relationship deepens as Percy stands up for her, and they share many tender moments as they figure out how to get Khione back home.
A possible plot could be that Percy and Khione have to team up to save a group of demigods who are trapped in a frozen realm. They start off as reluctant allies, with Khione being cold (both literally and figuratively) towards Percy at first. But as they face various challenges together, like battling ice monsters and solving puzzles in an ice labyrinth, they gradually learn to trust each other and become friends.
A possible plot twist could be that Percy's Titan - born nature makes him immune to certain types of magic that are usually harmful to demigods. This would give him an unexpected advantage in battles.
Well, one possibility could be that Percy is reluctantly drawn into Khione's service. Maybe she offers him a deal to save his friends or Camp Half - Blood from some greater threat. The plot could involve Percy having to use his unique skills and powers in ways that go against his usual moral code at first, but as he learns more about Khione's true motives, he finds a way to turn the situation around and defeat her in the end.