Introducing the Quest P.1

Percy, Thalia and Nico are sent on a quest to Hogwarts, to protect Harry Potter and his friends. The three must keep their identities a secret a while trying to gain the trust of Harry and his cautious friends. When the Triwizard Tournament is announced it seems their job just got a whole lot harder.
And there seems to be an old friend of theirs there as well.

Takes place in 4th year and after the giant war. There will most likely be inaccuracies and things that will change to fit my story.