When Percy Jackson is mistaken for Harry Potter by a group of Death Eaters while on vacation with Annabeth in Europe, chaos will ensue as the Order tries to set the couple free and Camp Half-Blood tries to find their missing leaders. The plot starts after the intro chapters. It's set just after the Giant War and in between the Order of the Phoenix and the Half-Blood Prince.

Dumbledore suspects Voldemort will make use of the Triwizard Tournament to get his hands on Harry Potter. So he seeks help from the Big Three demigods to protect Harry. Percy, Thalia, and Nico have to go to Hogwarts to protect Harry, undercover of a fourth participating school. But as suspicions rise, and Voldemort finds out about the demigods, will they get out of this alive?