Percy and The Revengers

(NOT PERCABETH/ THIS IS MY FIRST ONE SO BE NICE!) After Percy gains the Mark of Ladon and The Blessing of Athena, Percy heads to camp to prepare his proposal to Annie, but she is particularly distant and his friends look like they know something. Neeks tries to warn him, but as usual, Percy doesn't listen. When the time comes to propose he catches his Wise Girl in the act of cheating. He is preparing to go back home, but are attacked by old foes. When all seems lost, something ancient comes out of the void, or should I say something...