Harry stood in the Astronomy Tower, terrified. On the floor just above him, he was able to see a wandless and weak Professor Dumbledore cornered by Draco Malfoy, Bellatrix Lestrange, and Fenrir Greyback. The elderly headmaster was, unsurprisingly, acting as if he was having a pleasant conversation with the enemy and he looked completely at ease. Harry did not know where Dumbledore found his confidence at times.

He raised his wand at the opening, ready to strike if one of Voldemort's avid followers did so. Suddenly, Harry saw a figure out of the corner of his eye and he turned his head. Professor Snape was standing right by the stairs leading to the higher level, watching him.

"Severus?" Harry whispered, confused yet relieved. After Harry had fallen ill during his second year at Hogwarts School of Witchcraft and Wizardry, he and Snape became friends over the years. Their opinion of each other had changed after Snape had taken care of Harry in the privacy of his chamber in the school's dungeons. During that time, personal information was revealed from both sides and Harry and Snape now had a better understanding of one another. Harry was glad that his list of people he hated had lost a member.

Snape pressed a finger to his lips, pointing upwards. Harry nodded and watched anxiously, heart hammering, as the former Potions master surreptitiously made his way up the stairs. The Chosen One heard Bellatrix greet Snape and she goaded Dumbledore a bit more. Dumbledore looked immensely relieved at the sight of his colleague.

"Go on, now," Bellatrix said. "It's time!"

"Severus…"

The words were spoken so softly that Harry almost did not believe that it was Dumbledore who had said them. It scared Harry to see his normally very powerful headmaster be so weak and defenseless. He switched his gaze to Snape. The Hogwarts professor remained impassive, as if the situation had no affect on him whatsoever.

"Severus," Dumbledore pleaded. "Please."

Snape seemed to momentarily hesitate but he whipped out his wand and, much to Harry's shock, pointed it at Dumbledore.

"Avada Kedavra!" Snape cried.

A flash of green light erupted from Snape's wand and it hit Dumbledore squarely in the chest. Harry forced himself not to scream as he watched the headmaster's body fly over the railing and plummet to the ground. The Death Eaters stood still for a moment, as if making sure Dumbledore was very well dead, before rushing out of the tower. Harry returned to his senses and chased after them.

There were people who were duelling everywhere. Snape did not know how many Death Eaters there were or how they had even infiltrated the castle but he was certain of one thing: he had to leave. What he had done was not going to be taken lightly and Snape couldn't believe what he had done. He had just killed Albus Dumbledore. The former Potions master never wanted to do it; the old man had asked him to. Dumbledore had been dying, dying at the hands of a terrible curse that had been trapped in his blackened hand. Snape had tried his best to save his boss but his efforts had turned out to be futile.

Then it had come to Snape's attention that the Dark Lord had ordered Draco Malfoy to murder Dumbledore as a form of punishment for Lucius Malfoy's failure in the Hall of Prophecies at the Ministry of Magic the previous year. Being Dumbledore's spy among the crowd of Death Eaters, Snape had immediately alerted the headmaster. It was then that Dumbledore had asked his colleague to kill him instead of Draco not just because Dumbledore was going to die anyway but because he did not want the boy's soul to be damaged as killing tore at the soul. Snape was so appalled by the request that the bottom of his jaw had nearly been touching the ground. He had, of course, initially refused to accord this favor but had eventually given in. But now Snape was wishing that he had never given his word to Dumbledore.

Bellatrix was laughing like a madwoman as they stepped out into the grounds. Snape never liked Bellatrix, even during his time as a real Death Eater. He had always found her ridiculously eccentric and he also found her obsession with the Dark Lord quite disturbing; she practically kissed the ground he walked on. Bellatrix, in turn, did not like Snape either but that animosity mostly came from the fact that Snape had worked at Hogwarts under Dumbledore when the Dark Lord was believed to be gone and that now Snape was the one the Dark Lord trusted most. Snape took pride in irritating Bellatrix.

As they neared Hagrid's hut, Snape suddenly got the feeling that they were being followed. He received his answer before he even turned around.

"Snape!"

The spy whirled around and saw with a heavy heart that it was Potter running toward them. The boy was being foolish; he was practically asking to be killed! There was no way for Snape to protect him without blowing his cover.

A loud explosion resounded and Snape looked over his shoulder in alarm. Bellatrix had set the gamekeeper's hut ablaze and was now doing some sort of victory dance. Snape slapped a hand to his face and shook his head: so much for leaving discreetly. But then again, stealth was never one of Bellatrix's strongest points.

Potter was frozen in shock but he soon pointed his wand at Snape. The spy took out his wand again but kept it lowered as he waited.

"He trusted you!" Potter yelled furiously. Snape could practically hear 'I trusted you' in those words. "Sectumsempra!"

Snape hastily deflected the spell. Potter sent another one his way and this time it was returned to Potter, knocking him off his feet, when Snape deflected it. Snape approached the boy, placing his best cold expression on his face.

"Do you really dare to use my own spells against me?" he sneered icily. He watched Potter's eyes grow wide as the Gryffindor understood. "Yes, I am the Half-Blood Prince."

Snape had always known that Potter had found his old Potions book. It wasn't Potter using Sectumsempra on Draco Malfoy that revealed that piece of information to Snape; it was how Potter's Potions reputation had suddenly drastically improved. Potter was decent in the art of potion-making when he wasn't distracted but it was impossible for him to go from decent to excellent overnight! Snape had immediately suspected that his book had fallen in Potter's hands and he had waited for Potter to show it to him since he had become the boy's confidant but he never did. Snape had supposed that the boy did not one hundred percent trust him yet.

Snape kicked Potter's wand out of his hand before turning around and walking away. He heard Potter yell his name again and he broke into a run, rejoining his 'fellow' Death Eaters by the school gates.

I'm sorry, Harry. You'll know the truth someday, Snape thought as he Disapparated outside the school boundaries.

Harry made his way to the Hospital Wing, feeling numb. Snape had killed Dumbledore and was one of them. Just when Harry had thought he had his professor figured out he was thrown a curveball. He had thought Snape was his friend, a guardian-like figure; he was nowhere near a parent-like figure just as Sirius had once been but Snape had been much kinder that the Dursleys. Harry could not believe that his professor was not the man he seemed to be.

His hands curled into fists as he realized just how far Snape's betrayal went. He had not just betrayed Harry and Dumbledore but everyone else who had believed in him. Snape had played his role well and Harry was glad that he had never shown his Potions book to the former Potions master; Snape did not need to have his mind completely refreshed about the spells he had invented.

Harry reached the Hospital Wing and he found Ron and Hermione standing outside the doors. The Chosen One approached them and Hermione gave him a hug as Ron patted him gently on the back. Harry could feel Hermione trembling against him and he slowly pulled away, his heart heavier than ever.

"Oh, Harry," Hermione said with tears in her eyes. "I'm so sorry."

"Same here, mate," Ron added sadly. "Blimey, it seems that everyone you trust just leaves!"

"Ron! Be a bit more sensitive!"

"Sorry."

Harry shook his head.

"No, he's right," he said, his voice cracking slightly with hurt. "Sirius was killed by Bellatrix last year, Dumbledore was also murdered and Snape turned out to be a traitor like Pettigrew. That's three people now; I don't know how much more I can take."

"You still and always will have us," Hermione said consolingly. "And Ginny, and Ron's family and—"

"Ginny? Ginny! Is she okay?" Harry asked worriedly.

"She's fine, mate. That Felix Felicis of yours saved us all," Ron replied.

Harry breathed a sigh of relief. He made himself a mental note to go speak to Ginny before he left for his search of the Horcruxes. Speaking of Horcruxes, Harry dug in his pocket for the one he and Dumbledore had found but he no longer had it. Panic struck as Harry searched wildly for it but he then suddenly remembered that Dumbledore had been the one who had it last.

"Looking for this?" Hermione asked, pulling the locket from her own pocket.

"Yes! But how did you—?" Harry began.

"We found it next to Dumbledore at the foot of the Astronomy Tower and we figured that it was the Horcrux you went looking for," Ron answered quietly. "The problem is, it's fake."

"Fake?" Harry repeated, his heart beating slightly faster. "What do you mean?"

"We opened the locket and discovered a note written by someone named R.A.B. This person took the real Horcrux and vowed to destroy it, only we don't know if they had succeeded or not," Hermione explained.

Harry took the locket and turned it in his hands. Dumbledore had weakened himself for nothing by drinking the potion that had been guarding this worthless thing. Now the headmaster was gone to a place where Harry couldn't reach him. Harry gripped the locket tightly and hot tears spilled out of his eyes. Hermione embraced him again and he could hear her sobbing quietly onto his shoulder and he could also see a stray tear or two sliding down Ron's face. As he and his friends stood crying, Harry wondered whether this was only the beginning of their heartaches.

I'm back with the sequel of A Potions Master's Remedy! What do you guys think of this one so far? It feels like Harry and Snape's friendship has just begun even though four years have passed and already it falls to pieces! What will happen next, I wonder? Stay tuned to find out!