"No...no way...that's just...impossible!" I gestured wildly to Principal Nicholson's outstretched palm. "Allison, when you're an Elemental, nothing is impossible. And you, my dear, are one of them. One of us." "I'm...I'm an Elemental?" Looking down at my hand, everything just fell into place. The pale blue snowflake gleamed slightly, branding me to the Mystique realm. In Principal Nicholson's hand was a tiny lightning bolt, floating just above her palm. "Yes, yes you are."

The seven have finally had a few years of peace. But when an accident involving the river lethe happens due to Nico's deception, Percy is once again left clueless and confused. Nearby, the forces of darkness decide to take advantage of Percy's newfound memory loss. Will he be able to tell where his real loyalties belong?