Paul got a job offer at Casper High. He's going to teach Mixed Grades English. When things start going awry, Paul excuses Percy. But what happens when Paul starts noticing Danny Fenton keeps asking to be excused at the same time as Percy? Percy just got home from the Giant War. He's shocked to see everything in boxes. When he finds out Paul and Sally are heading to Amity Park for the school year, he tags along and heads to Casper High for senior year, while Annabeth heads to Boston to look for her cousin, Magnus. When strange things start happening, Paul excuses Percy, but what happens when there is a ghost boy always right behind him. And why does Danny keep disappearing? Danny is tired. He keeps fighting the same ghosts day after day, but they just keep coming back. Along with some other ghosts that Danny's never seen before. When an old friend of his mom shows up with her son, Percy, and husband, Paul, who is going to be teaching English this year. But when Danny notices Paul keeps excusing Percy every time a ghost attacked, he starts to get curious about Percy's past. What will happen when Danny starts investigating Percy?