Harry shifted in the sleeping bag, which was on the hard, stone floor of the Potions classroom. 

At his desk, Snape was bent over a cauldron, putting in ingredients.  His breathing was slow and he muttered to himself.

"Could you stop talking?" Harry blurted out, then covered his mouth.

"Potter!  I'm trying to brew the Draught of Living Death and if you don't shut your mouth, I might want to use it on you."

"Sir, you just tried out the truth potion we made earlier on me..."

"Potter!"

"Sorry, I can't help it."

"I know you can't," Snape growled, "but at least try to not blurt out the truth!"

Harry sighed.

"What was that, Potter?"

"A sigh," he blurted out.

"A sigh," Snape repeated. "Potter, if-"

Suddenly, Dumbledore entered the room.

"Professor Dumbledore, sir," said Snape, inclining his head slightly and removing the scowl from his face.

"Severus," Dumbledore said, "I have heard you gave Harry here truth potion, did you not?"

"Yes, I did," Snape said, the trace of a sigh recognizable in his voice.

"Severus, why?  You have corrupted Potter's 'social life' by doing this," Dumbledore said.

Harry listened, pretending to be asleep.

Snape replied, "He raised his hand."

Harry suddenly sat up. "No, I didn't!  I scratched my head!"

"Well," Dumbledore said, "It seems as if Harry is awake, then.  Now, if he really has taken this potion, it appears that he only scratched his head."

"Perhaps."

"Severus, why are you being so harsh on him?"

"Professor, I have never been harsh to Harry."

Dumbledore looked at Harry. "Harry, tell me the truth, for it is all you can do.  Has Professor Snape here been harsh on you?"

"Oh, yes," Harry said, "All the time."

"Ridiculous," spat Snape. "He is lying!"

"Severus!" Dumbledore said slowly, yet with a slight edge to his voice. "Harry cannot lie.  I will make sure I tell everyone in the castle that Harry cannot help but blurt out the truth."

Snape glared at Harry, then looked back at Dumbledore. "You will not tell them it was I who gave him the potion?"

"No, but I would not like this to happen again." Dumbledore's voice was calm.