Just imagine if all your favorite characters united to fight evil? What kind of unprecedented power, combining Greek and Egyptian magic, will it be? Rick Riordan gives you a unique opportunity to find out what will happen if Percy Jackson, Carter Kane, Annabeth and Sadie are on the same side! Serapis - both a Greek and an Egyptian god - has risen and wants to take over the world. It is almost impossible to defeat him, because even the most powerful spells have no effect on him. But everything can change if demigods and magicians finally start fighting together!