Cordelia Liu's first year at Shadow School was a success. But her second year is already different. Ghosts are refusing to move on, the teachers are acting weird, and Cordelia's best friends, Benji and Agnes, aren't as interested in rescuing ghosts as they used to be. Benji is busy hanging out with the girl he befriended over the summer, while Agnes spends all her time building a machine that might be capable of dehaunting the school forever.