Christine was lying awake, wondering whether it would serve any purpose to change night-dresses, when the mirror suddenly spoke up.
"Christine, it is time we had a talk."
Christine shot up out of bed, and zoomed to the door.
"I have locked the door, you will find, to ensure that this conversation takes place."
Christine gaped at the mirror. "You're mad, Walter!"
The mirror, which was really the Ghost, or once Walter Plinge, ignored her. "Christine, it has come to my attention that this is the first time you have slept in your room since you came here."
"So!" Christine squeaked. "Why would that bother you!"
"Who was occupying this room when you weren't here?"
There was a silence following those words, which interestingly seemed to echo Christine.
"Do you mean to tell me it was Perdita I was teaching?"
"Teaching! I haven't the slightest idea what you mean!"
Walter sighed again, through the mirror. "Sing for me, Christine."
There was a pause. "The 'Departure' aria."
"Kesta? Mallydetta! Porter see bloker! See bloker komoonekayuu?-"
"For the sake of my ear drums, shut up."
Christine sulked. "Well! You wanted me to sing it!"
"I have heard all I needed to hear from you. I would now simply like to know how it is you could possibly think that you sang better than Perdita."
"Well, people applauded me! Though I must say, I would have expected her to sing a bit quiter, so people could hear me!"
A strange noise came from the mirror, sounding oddly like a man smacking a mask-clad forehead. "Never mind. Your stupidity confirms all, Christine. Goodbye."
"Goodbye! Please unlock the door!"
A week, later, when Agnes returned to Ankh-Morpork, Bucket found a letter sitting on his desk. With a giant gulp of water, he picked it up and read it.
Dear Mr. Bucket,
It has come to my attention that Christine sings like a locomotive. Bugger. I would therefore like Miss Perdita X Nitt to sing the role of Canine in Les Chiennes tonight. Please send Christine as far back into the chorus as you can. She requires severe tutoring in every subject ever conceived of. I hope your cough is better, and that ballerina who twisted her ankle remembers to be more careful next time.
The Opera Ghost