“I haven’t been anywhere near your office!” said Harry angrily, forgetting his feigned deafness.

“Don’t lie to me,” Snape hissed, his fathomless black eyes boring into Harry’s. “Boomslang skin. Gillyweed. Both come from my private stores, and I know who stole them.”

Harry stared back at Snape, determined not to blink or to look guilty. In truth, he hadn’t stolen either of these things from Snape. Hermione had taken the boomslang skin back in their second year—they had needed it for the Polyjuice Potion—and while Snape had suspected Harry at the time, he had never been able to prove it. Dobby, of course, had stolen the gillyweed.

“I don’t know what you’re talking about,” Harry lied coldly.

“You were out of bed on the night my office was broken into!” Snape hissed. “I know it, Potter! Now, Mad-Eye Moody might have joined your fan club, but I will not tolerate your behavior! One more nighttime stroll into my office, Potter, and you will pay!

“Right,” said Harry coolly, turning back to his ginger roots. “I’ll bear that in mind if I ever get the urge to go in there.”

Snape’s eyes flashed. He plunged a hand into the inside of his black robes. For one wild moment, Harry thought Snape was about to pull out his wand and curse him—then he saw that Snape had drawn out a small crystal bottle of a completely clear potion. Harry stared at it.

“Do you know what this is, Potter?” Snape said, his eyes glittering dangerously again.

“No,” said Harry, with complete honesty this time.

“It is Veritaserum—a Truth Potion so powerful that three drops would have you spilling your innermost secrets for this entire class to hear,” said Snape viciously. “Now, the use of this potion is controlled by very strict Ministry guidelines. But unless you watch your step, you might just find that my hand slips”—he shook the crystal bottle slightly—“right over your evening pumpkin juice. And then, Potter . . . then we’ll find out whether you’ve been in my office or not.”

Harry said nothing. He turned back to his ginger roots once more, picked up his knife, and started slicing them again. He didn’t like the sound of that Truth Potion at all, nor would he put it past Snape to slip him some. He repressed a shudder at the thought of what might come spilling out of his mouth if Snape did it . . . quite apart from landing a whole lot of people in trouble—Hermione and Dobby for a start—there were all the other things he was concealing . . . like the fact that he was in contact with Sirius . . . and—his insides squirmed at the thought—how he felt about Cho . . . He tipped his ginger roots into the cauldron too, and wondered whether he ought to take a leaf out of Moody’s book and start drinking only from a private hip flask.