War of the World, book 1: A Great War, a PJO/HOO AU (Discontinued)

The Bosnian city of Sarajevo is expecting a visit from Archduke Franz Ferdinand. Little did everyone knows, this visit will start a great war, a war greater than Napoleon's, a war that divides the world. The War to end all War, the Great War.
Percy is a British visiting Sarajevo just a few days before the Archduke visit. Same with Frank. They met under stressful circumstances. Will they get through the first few months of this new war, or will they fail?
Disclaimer: I do not own the characters, only the plots, the character owned by Rick Riordan.