While you were attending classes, Ceridwen went over to the principal's office, disguised in her tutor form, and went over to the principals office to sign up for the tutoring job. Hours later, the goddess was hired, and assigned to become your tutor, and left the office to find any clue of where you could go for Halloween.
Just then, Ceridwen stopped by, and noticed a flier on the wall, and pulled it off. The flier says "Halloween Ball At Town Park, hosted by the Principal. All Students welcomed." With that flier, Ceridwen kept it hidden in her breasts, and walked out of the room to go outside, where she sat on a bench outside of the school. "This Halloween Ball should be enough to give Light the chance to change everyone with the TF-Note," she says. "Let's hope he'll be satisfied at the end of his writing."