The Time of Magic and Myth.
A Harry Potter, Percy Jackson crossover.
After the war of Gaia, Nico received a strange task. Nobody knew what it was, but Hades had assured them that he was not missing, just in a different place.
One by one, the seven also went missing, and the gods said they were going to the same place that Nico went. A different world, they said; one of Hecate's dimensions.
Harry has just arrived at the order, and after finally getting over his friends secrecy, he is spending time with them before going back to school for the fifth year. And yet someone strange has just arrived with Dumbledore... A fifteen year old boy, with pale olive skin and black muggle clothes.