Percy would likely include details about the magic items he's used. For example, Riptide, his trusty sword that can turn into a pen. He'd talk about how it felt in his hand during battles. Also, he might mention the food at Camp Half - Blood, like the ambrosia and nectar that healed him. Another detail could be the pranks he and his friends played on each other at the camp.
When Percy tells his story, he would include details about the prophecies he was part of. The pressure of having to fulfill a prophecy and how it affected his decisions. He'd also talk about the different powers he discovered he had as a son of Poseidon. Like controlling water, which he used in many of his battles. And he might share some of the inside jokes and traditions at Camp Half - Blood that only the demigods know about.
He might sing sea shanties. Given his connection to the sea as Poseidon's son, shanties would be a fitting choice. They could also be ancient Greek hymns that he somehow remembers from his demigod heritage.
Percy might meet an old enemy who has somehow been resurrected or changed in the future. This enemy could be more powerful and have a new plan to take over the world or destroy the demigods. Or he could meet a group of time - traveling demigods from an even further future who are trying to fix something in Percy's future that has gone wrong.
There's a chance that it could be a character from Percy's family. For example, a distant relative who has been corrupted by some dark magic. They might betray Percy for their own gain or because they are being controlled, and this betrayal could lead to Percy being killed.
He might encounter new demigods who are also on the run or hiding from the traditional demigod society. These could be demigods with different powers or backgrounds that Percy has never seen before.
Well, if Percy tells his story, it would surely include his adventures at Camp Half - Blood. He'd talk about his first discovery that he was a demigod, his encounters with the various monsters like the Minotaur. He might also mention his friends, like Annabeth and Grover. Their quests together, such as the search for Zeus' lightning bolt, would be a major part of the story. Percy would probably share how he felt during those dangerous times, the fear and the determination to succeed.
Perhaps it's a gift from his father, Poseidon. Since Poseidon has control over the sea and all things related to water, he might have some connection to a power that gives Percy wings, like as a way to help Percy reach new heights both literally and metaphorically.
Percy might run into Loki. Loki is known for his trickery. He could either befriend Percy for his own devious plans or try to deceive him. Percy, being used to dealing with tricky situations in his own world, would have to be on his guard against Loki's schemes.
Chiron, the centaur mentor at Camp Half - Blood, might get involved in the rescue. He has a vast knowledge of the demigod world and could use his wisdom and connections to track down Luke and free Percy. Also, some of the other demigods at the camp who look up to Percy might volunteer to help, like Clarisse. She may not like Percy much, but she wouldn't want a fellow demigod to be in the hands of Luke.
They could go on a quest to find a magical artifact that has the power to keep both the demigod world and the Twilight world in balance. Percy's skills in combat and his knowledge of mythology would be useful, while Bella's ability to understand the motives of vampires and werewolves could help them avoid certain dangers.
He might create a flying machine. It could be a small, personal device that uses some sort of anti - gravity technology. This would allow him to quickly travel around the city or reach high - up places easily.