The mistery of the disapearence of the Hogwart's ghost continued being unsolved. The proximity of the first task of the tournament had put an stop in the search for the ghost, so the school's champions could train and the advisors could be ablailable if necesary. But after the first task Cedric, Harry and the rest of the demigods were recruited again by the Headmaster to look for an answer.
Neither of them minded as looking for clues in the castle, as it was a great adventure. Not every student could say that they had been in the less used parts of the castle, most of them forbidden. The long corridors filled with armors that instead of being still in their pedestal, walked arround their corridors looking for a fight with other armors and the demigods had more than once had to fight their way back to the main part of the castle. The clases not used anymore had, in some cases, magical creatures, that provided a good practice for DADA spells and curses.
But no matter where they looked, from the greatest hall to the smalles alcove, the highest tower or lower dungeon, the ghost of the Grey Lady didn't appear and not a clue could be found. The demigods soon found themselves in a room on the seventh floor, with lots of things left or forgotten over the years, a great treasure to discover, but no time to do so because of the missing ghosts.
It was the day, before the winter holidays when a group of demigods cornered Nico di Angelo, the son of Hades was cleary the most knowledge in the subject. The boy cleary knew something, but he had said nothing, so they had grouped to presure the young boy. He ended confessed that he was guilty and explained that Helena Ravenclaw unfinished busines was the tainted diadem of her mother, and now that he had destroyed it she had gone to the next adventure. He had kept silent so he had an excuse to talk to the other ghosts of the castle. The other demigods decided that even if the adventure of the exploring of the castle had been a great conpensation for the silence of the boy, it was time to tell the truth.
The demigods ordered Nico to tell the headmaster while the rest went to the seventh-floor room to explore and see if there was something usefull.
Telling Dumbledore the story hadn't been what Nico would have wanted, the old wizard had many secrets and appeared to be able made people tell him all his secrets. The headmaster had put a deceptioned grandfather face, and Nico was happy went the whole thing ended, before he could tell more that what was needed. He had tell that he had talked with all the ghost in the castle, and enjoyed greatly their company. How he had found Helena and how she had trusted him with her secrets. He finished telling the headmaster that Helena's unfinished businesh, that kept her in the castle had been resolved, and that he would honor the woman keeping her secret safe.
After having answers some questions from the Headmaster, giving no more information about the matter, he was let go. Nico bolted from the ofice before the old wizard changed his mind, and spend the rest of the day investigating the room on the seventh floor with the rest of demigoods