Hogwarts Crossover- Darker Secrets

Following their eventful second year at Hogwarts, Percy Jackson, Annabeth Chase, Sherlock Holmes, John Watson, Hermione Granger, Ronald Weasley, Harry Potter, Katniss everdeen, Peeta Mellark, Augustus Waters, Hazel Lancaster, Tobias Eaton and Tris Prior embark on their second year at the magical school.
In the third instalment of the Fandoms United series, the thirteen of them try their hardest to find out if there is a way to save Percy from his destiny, or whether they will have to let the Shadow Lord take over his soul. There will be sadness, and there will be joy, but in the end the curse states it all:
If the 12 of them stand tall
The danger against them shall fall.
But if 13 are still alive,
The danger against them shall thrive.
The greatest sacrifice you can take,
Must be made for the others sake.
They must fight hard through all the pain,
Lest their friends death have been in vain...