Sectumsempra….

The word from the Prince’s potions text popped into Harry’s head just as he ducked into a small space beside a stall, barely shielding himself from one of Malfoy’s blasting hexes. The very instant the peculiar curse crossed his mind, along with the brief but presently alluring description—“for enemies,” it read—he was seized by a terrible curiosity to find out just what that meant and an equally overwhelming desire to test it out on Draco...

Intentions set, Harry carefully peaked beneath the stalls in search of his target’s location; he spotted the pair of top dollar dress shoes he was looking for on the other side of the washroom, gently sloshing past a sink where shards of porcelain and tiny bits of stone surrounded its spurting pipes.

Harry crouched low and peeked around the corner. Adrenaline rushed through his veins as he raised his wand and took aim with the curse on the tip of his tongue, but a beat shy of the word tumbling past his teeth, a thought occurred to him.

What if the Half-Blood Prince was indeed a dark wizard?

It was a suspicion that Harry had occasionally entertained but never fully explored as he thumbed through the text by wand light. After all, what aspiring dark wizard leaves behind a potions manual filled to the brim with tips on basic brewing? There was hardly any room for a nefarious scheme in that; yet, even as he reassured himself, his mind wandered back to that encounter with Tom Riddle during his second year. Who would have thought a diary full of empty pages could be so poisonous?

If the Prince’s spell did do more than immobilize Malfoy, more than knock the Slytherin on  his pompous ass...if it killed him...

Harry’s insides knotted at the thought, and suddenly the spell didn’t seem as appealing as it had just moments earlier. A grotesque image of Draco’s body, lying pale and limp on the rapidly flooding stone floor with ribbons of blood tinging the water pink, effectively ended that train of thought. Perhaps a body bind would do instead.

The Gryffindor, who up until that moment, had been poised to strike, had lost sight of his opponent during his brief distraction. A quick scan of the opposite side of the room gave away nothing about the would-be Death Eater’s new position, so Harry cautiously navigated around the debris towards what was left of the sinks.

Half way there, his attention was jerked away by the sharp, nasally voice of the Potions Master subtracting points indiscriminately on the other side of the double-doored entrance. It was in that fraction of a second, when Harry’s full attention was on his approaching doom, that a brilliant burst of energy sent him crumbling to the ground.

White hot pain, like a thousand burning knives, sliced through flesh and bone. If he opened his eyes, surely he’d see that his body had been flayed, that his skin had been stripped to expose the bloody tissue beneath, but...no, no this agony was familiar. There’d be no blood, because this was an Unforgivable. This was the Cruciatus.

Even as his body writhed under the effects of the curse, he could hardly believe it was true, but then his core twisted in on itself and fiery jolts sent his limbs flailing wildly, and his brain stamped out all thoughts on the matter, deciding that there was little time for clear thinking anyhow. More important was the fact that with his lungs unable to expand, there was no air to form a scream or call for help, and help was something he desperately needed just then.

Malfoy was approaching slowly, his face unnaturally serene except for the murderous glint in his eyes. He was lighter in step than Harry had seen him all year, as though he had just solved some vastly troubling dilemma.

And then the blond was leaning over him with a grin, saying...something, but since the curse was still streaming from his wand, Harry wasn’t able to focus on much else beyond the pain. Muscles all over continued to jerk and contract, splashing water and kicking debris in all directions.

And suddenly it stopped…at least the main source of the pain did. Harry’s body still shuddered with residual spasms, though it wasn’t nearly as excruciating.

When Harry had gained enough control of his body to roll his head toward his attacker, it was to see a cowering student, unarmed and terrified—much like he had looked before this whole disaster—and a shadowy figure advancing on the boy. It was definitely a teacher. From what he could make out of the generally pale form enrobed in black, it was most likely Snape; although for all he knew, it could have been McGonagall. His vision was starting to gray and blur around the edges.

While the release of the curse had been a welcomed relief for his whole body, his lungs especially, he could feel pressure slowly starting to build in his chest. He’d been subjected to the cruciatus curse before by Voldemort’s hand and the effects hadn’t been this catastrophic. Something wasn’t right, something besides the agonizingly sensitive nerves. Apparently Snape/McGonagall—no definitely Snape, Harry decided upon further inspection—who had ignored his presence until that moment, flung himself in front of Harry’s face as though he had noticed it, too. He was moving his mouth angrily, but no words were coming out…at least not ones that Harry could hear.

Harry saw Snape pull out the two vials and knew what was coming next, but he was prepared for neither the vinegary taste of the potion nor the horrendous texture. The results were well worth it, though. No pain. No twitching. No panic, but he still was having difficulty breathing.

Trying to focus on anything but the constriction in his chest, Harry paid close attention to his teacher’s face—something that his sense of self-preservation usually urged him to avoid on most occasions, but for some reason it was acceptable now. He looked livid; but from Harry’s current vantage point, it was not the dark eyes that terrorized Hogwarts students of all houses, not the steep slope of the hooked nose that forced itself in everyone else’s business, not even the tiny little bogie dangling delicately from his flared nostril, but their proximity to his own face which made the former Death Eater look both immensely disturbing and comical all at once. Harry would have laughed out loud, if air weren’t in such short supply.

Then Snape darted alarmed eyes to something to Harry’s left, and before the Gryffindor knew what was happening, the world began to tilt…or rather, he did. And Malfoy, who Harry suddenly realized had been huddled in the corner for some time time, was watching Harry just as intensely as Harry was watching him. He was idly aware that Snape was doing something to his side, but Draco, who was becoming greener by the second, was fast becoming the more interesting subject.

But he was feeling sleepy, now, and his lids drooped lazily despite the freezing cold water that drenched him. The last thing he saw before his eyes fluttered shut was Draco Malfoy emptying his stomach on the bathroom floor.

How odd, he thought, what a mess…

Then Aunt Petunia was slapping his cheek, trying to wake him up.

Five more minutes…just five and he’d fix the Dursleys their breakfast…just five…