Snape did not take them far. He entered an empty classroom nearby, ushered Harry inside and closed the door behind them carefully. He paced a few steps up and down in front of Harry before he opened his mouth to speak.

”I have been falsely accused, Mr Potter,” started Snape. 

Harry raised his eyebrows. 

”…of performing this Christmas Enchantment that everybody goggles and sighs so foolishly about. I have set out to get myself cleared of all suspicions and hand the perpetrator over to the headmistress to receive her infinite gratitude and undying love, of which I want none,” Snape finished decisively.  Harry quirked his lips imperceptibly.

”What make you believe I have something to do with it, Professor?” he asked lightly.

”Don’t play the innocent with me, Mr Potter,” Snape answered impatiently. ”You and your friends overheard Minerva’s little lecture yesterday. At least Miss Granger is smart enough to draw the right conclusion from those ill-advised words. And it was becoming pretty obvious that the Enchantment was late in manifesting this year. Minerva was clearly desperate. Just like you to step in and save your head of house. Now tell me, what did you do?” 

”We didn’t do anything. Hermione was just as surprised this morning as everybody else by the nascent Christmas spirit and she thought that you had changed your mind. Tell me Professor, why would you not help Professor McGonagall out in a trifling matter like this, when it is clearly so important to a lot of people?” Harry asked crossly.

”A trifling matter? Did Miss Granger show you the requisites of that Enchantment? You need a lot of power and advanced skills to perform it,” snorted Snape.

”What do you mean? It doesn’t crave any special skills!” protested Harry. ”Hmm…” Harry bit his tongue too late and coloured slightly. Snape looked smug.

”So you did have a look at the text. I bet Miss Granger researched it for you. I modify my statement - the Enchantment per se only takes moderate skills and power, but the conditions are very precise and, as I see it, they are impossible to circumvent. Now how on earth did you make it work?” Snape stepped closer to Harry and fixed him so intently with his black eyes that Harry was afraid he would try to Legilimency him.

”I know how to block you, Professor,” Harry felt obliged to point out. He had found himself in much better control of his emotions after he had gotten rid of Voldemort’s piece of soul that had been attached to his as a Horcrux until last spring. He had learned to master Occlumency on his own the past summer. It had come perfectly naturally to him and had helped him through the bothersome attention of the press.

”I suspected as much, Potter!” exploded Snape. ”You’re not fifteen any longer and you have conquered a Dark Lord - of course you can block me out! That’s not the issue. What I want to know is how you and your friends found a way to circumvent that precise requisite of the spell.”

”We didn’t circumvent…” began Harry, but was interrupted by Snape again who grabbed his arm.

”I resent other people being cleverer than me, Mr Potter, that’s all,” said Snape with self-imposed calm. ”Frankly, I’m not used to that. I just want to know how you did it - I tried every possible way to fool the Enchantment but it wouldn’t work. I simply want to know what I missed.” Harry stared at him.

”You tried to find a way to circumvent it? But why didn’t you just do it then? You’ve performed the spell before - Professor McGonagall said so?” exclaimed Harry befuddled. 

Snape turned away with colour rising on his cheeks. Harry stared at him. Suddenly he drew his breath and grabbed Snape’s arm in return. 

”Are you ill, Professor? Are your powers reduced? Is that why you couldn’t do it? I’m so sorry…” Harry’s voice was full of concern and compassion. Snape coloured even deeper and tore his arm away, highly embarrassed.

”I’m perfectly fine, Mr Potter, thank you very much,” he snarled haughtily. ”With Voldemort gone, I have in fact never been in better health. I’m afraid there is little chance of watching me waste away in disease, at least in the immediate future.” Harry recoiled a little and inclined his head to the side in genuine puzzlement. 

”But I don’t understand then, why you would try to circumvent the Enchantment…? Oh…” Harry fell silent as he realised what it must mean.