When Two Worlds Cross; Percabeth

After the war, Percy and Annabeth just want to spend some time with each other for the rest of their school year. And for once they get to relax for the last few months of their Junior year. But when they hope to have the same senior year, a new prophecy was said and the couple, the rest of the seven, and some additions have to travel to a new world. To protect a boy that was marked at the age of one by a killer. They have to find two half-bloods in a year of chaos. If the dark wizard finds out what they are, then there is no telling what he will do with the information.
They know there is no point in trying to prevent the prophecy. No one knew that a tournament of challenges would end in death and despair.
What had the Demigods gotten into?

I will be changing the Harry Potter story a little bit, like a character that is kind of evil in the original books actually being nice and someone taking their place and such.

This story takes place after HoO and during the fourth Harry Potter book.
Disclaim: I do not own the Percy Jackson characters or the Harry Potter characters or the main story plot that follows the Goblet of Fire timeline when they reach the wizarding world. But I am adding some other things to it which are all mine.