As you can surmise from the chapter title, it looks like Harry's secret gonna be blown. Here's how it happens:

Chapter Four- The Discovery

Harry sighed with relief when he woke up. It was Sunday. He had actually made it through the first week without slipping up. And thanks to Snape, he hadn't felt the urge to drink blood. He felt like his old self. It was a great feeling.

Springing out of bed, Harry got dressed and went down to the library. He was feeling so good, he decided to do the homework he neglected Friday and Saturday. Maybe afterwards, he would just take a nap outside.

"Hey, Harry. Why weren't you at breakfast?"

Harry opened his eyes and saw Ron standing in front of him, blocking out the sun. Closing his eyes, he let his head droop down before saying, "I wasn't hungry," in a flat tone.

"You're never hungry! What's the deal?"

"Nothing. I just don't feel hungry nowadays!" It was true. Harry had no need for food. His stomach had changed and only accepted liquids, like blood. At the thought of blood, Harry's eyes strayed to Ron's neck. Maybe, just a taste...

Immediately, he shook himself out of his thoughts. He couldn't attack Ron! Ron was his friend. What was he thinking? Getting up, Harry mumbled that he needed to use the bathroom and took off into the castle.

"Potter, I've been looking for you," Snape's voice called from behind him in the hallway.

Harry stopped and turned to the professor, head down. "Yes, sir?"

"Five points from Gryffindor," Snape began. Harry's head snapped up, eyes looking quizzical. Snape smirked, "for not looking at me when I'm speaking to you."

"Sorry, sir."

"I believe that you need this," Reaching into his robe, Snape produced a flask of Harry's potion. Harry gratefully grabbed it and consumed it. "Thank you, sir."

"Whatever. If you'll excuse me, I need to give Lupin his dosage. Oh, and I am taking five points from Gryffindor." Snape turned and left, his robes swirling behind him. Harry, feeling in control again, headed for the common room, unaware that someone had witnessed the entire scene.

'I don't believe it. Harry's a...vampire?' Hermonie leaned against the wall, eyes wide with disbelief.

'It can't be. Otherwise, he wouldn't be able to go out in daylight. But, how do you explain the pale skin and fangs?' Stunned, the bushy-haired girl wandered outside and spotted Ron sitting on the grass before heading toward him.

"Ron, I think I know what's up with Harry. Mind you, I could be wrong and we shouldn't come right out and accuse him. On the other hand-"

"Hermonie, spit it out!"

"I think Harry's a vampire."

Ron burst out laughing. "Hermonie, that has got to be the most ridiculous thing you've ever said."

"See? I could be wrong. We could ask him and I could confront him with what I saw."

"What did you see?"

"I saw Snape give Harry some kind of potion. Before that, I saw a pair of fangs when Harry spoke to him."

"Are you sure?"

"Quite sure. I'm going to wait for him in the common room."

"I'm coming with you."

The two teens headed inside, up to the entrance, spoke the password, stepped in, and froze. There, sitting in an armchair reading, was Harry. The pale boy looked up and gave a closed lip smile like usual.

"Harry, can we ask you a question?" Hermonie asked. A nod. "Harry, are you a vampire?"

Harry shook his head insistently. He felt bad lying to his friends, but he didn't want to lose their friendship.

"You know you can tell us. If you had become a vampire, we would stick by you and not tell anyone else."

Avoiding eye contact, Harry said, "Would you really?"

"Of course. By the way, I saw you talking to Snape earlier."

"What exactly did you see?"

"Well, it may have been a trick of light, but I thought I saw you with fangs."

Harry was sure that if he wasn't already pale, he would be now. Hermonie saw everything. She knew before asking, but was considerate enought to not force him to admit it. Taking a shaky breath, he looked up at his friends. "You saw correctly. I'm a vampire," he admitted, fangs showing as he spoke.

"How?" Ron gasped.

"Voldemort. When he was revived, it was as a vampire."

"Why didn't you write to us?"

"Dumbledore has me acting as a spy so I couldn't tell you."

"You're spying on You-Know-Who?"

"Uh-huh. Voldemort believes I'm on his side. He doesn't know that I'm not."

"What was that potion Snape gave you?" Hermonie asked.

"It is to help me curb my need for blood. It's like Lupin's Wolfsbane Potion."

"Does anyone else know you're a vampire?"

"Aside from you and Snape, the entire Order knows."

"Do you think you'll finish school without everyone finding out?"

"I hope so. I lasted a week."

Hermonie hoped so too. It felt so unreal. One of her best friends was an undead being and was playing spy for Dumbledore. The whole thing was risky. What if Voldemort found out that Harry was double-crossing him? Would he get rid of Harry?

'I really hope you know what you're doing Harry because you're playing a dangerous game.'

Well, Ron and Hermonie found out, but will anyone else? Chapter Five will answer that question.