A/N: I'm back :) And this is actually a repost - I haven't written in so long, I totally missed a MAJOR detail. Enjoy!

As the three approached the gates of Hogwarts, Dumbledore turned abruptly. "Sirius, do we have the mirrors?"

Sirius nodded, pulling two identical mirrors the shape of small picture frames out of his pocket.

At Harry's inquiring look, he said "James, Remus and I used to take turns using them to communicate in separate detentions. We're going to use them tonight in case we get separated. Dumbledore will have one and we'll have the other, all we have to do is say the other person's name."

Dumbledore grabbed the mirror and continued walking. They walked to the edge of Hogwarts grounds in silence, then Dumbledore turned to Sirius. "Do you know where we're going?"

Sirius nodded solemnly. "We'll be right behind you."

With that, Dumbledore turned on the spot and left. Sirius held out his arm and Harry grabbed it obediently, steeling himself for the unpleasant sensation of aparating. "Harry," Sirius started gravely. "We're going to aparate into the ocean and we have to swim to the cave - just prepare yourself. It could be rough conditions."

Harry nodded and a moment later, he experienced the familiar sensation of being squeezed through a tube. He opened his mouth to catch his breath, but ended up swallowing salty water before strong hands pulled him up above the waves. "Come on, it looks like Dumbledore's already there," Sirius shouted, beginning to swim towards the looming cave. Harry followed, his soaked clothes chilling him in the icy water.

When they climbed up the rocks to the cave's mouth, Harry was shivering against the cool breeze. Sirius scrutinized him and Harry saw him flick his wand by his side. His clothes were dry a moment later and he gave Sirius a grateful smile before turning to the headmaster.

Dumbledore nodded towards the dark depths of the cave. "I have reason to believe the locket is in here. We must be careful - I'm sure it will not be easy to excavate."

Sirius ignited the tip of his wand and followed behind Dumbledore, Harry walking quickly to keep up. When they reached the end of the cave, Harry looked at his father confused. However, Sirius looked grim. "What do we need to do to pass?"

Dumbledore sighed. "I think it wants blood."

"I'll do it," Sirius said firmly, pulling a small blade out of his robe pocket.

Harry eyed the blade wearily. How much blood would Voldemort want someone to shed to get through? He didn't like the answer he was coming up with in his mind.

Sirius cut his forearm and allowed the blood to spill onto the wall. The wall vanished, and Sirius tapped his wand gently against his arm, the cut magically resealing. Harry stepped forward, but Sirius held his arm out and looked at Dumbledore.

Dumbledore inhaled deeply. In front of them was a dark, still lake. In the center was what appeared to be a stone basin, the only light in the cavernous room emitting from it.

"Surely we won't swim through that?" Sirius mumbled to Dumbledore.

Dumbledore shook his head. "No, I don't think that would be a good idea. This water isn't regular ocean water…"

Harry swallowed thickly. The lake at Hogwarts had dangerous creatures in it - he could only imagine what swam in these dark depths.

"Let's feel around the walls - be careful not to step in the water. I think that's imperative." Dumbledore instructed, moving around the cavernous room with quiet agility. Harry followed Sirius toward their right.

After a few minutes of quiet searching, Harry stepped on something that felt lumpy under his shoes. "Sirius," he hissed, taking a step back. "It's a rope."

Sirius immediately doubled back. "Dumbledore!" He called out, his deep voice echoing through the cave.

They waited a minute or two before they heard the gentle steps of the headmaster. "What is it?" He asked, darkness engulfing them.

"Harry found a rope," Sirius said, taking a step away from it and pulling Harry with him. Dumbledore leaned over and pulled. Harry expected something dangerous to happen, but all that emerged was a small wooden boat.

"There's only enough room for two," Sirius croaked, looking at Dumbledore warily.

Dumbledore nodded curtly. "As I expected. Voldemort didn't want to make it easy. Sirius, I think it best that you stay on the shore here. I'm not sure what Harry and I will find in the middle, but having your eyes here might be useful. Harry - will you come with me?"

Harry swallowed thickly and looked up at Sirius. He was surprised that the man wasn't reacting - he fully expected Sirius to pull him out of harm's way and insist he go with Dumbledore. However, Sirius merely nodded at him.

Dumbledore moved to step in the boat and Harry made to follow. However, he felt a cold hand grab his shoulder and pull him back. Sirius held him close for a moment and Harry felt him kiss the top of his head. When they pulled apart, Harry could see the worry etched in Sirius's eyes.

"Be right back," Harry whispered in an attempt to reassure his dad. He turned and stepped in the boat. Dumbledore tapped the oars and they made their way across the glassy lake. Harry sat there tensely, waiting for something dangerous to happen. He was surprised when they bumped against the island with no magical run-ins. This seemed too easy…

"Alright Harry," Dumbledore said as he approached the basin. "This is a potion. It appears, to reach the artifact at the bottom, I must drink it. I want you to promise me that, no matter how much I beg and plead, you make me drink it fully. Only then can we retrieve the horcrux. Don't do anything else until I have drunk the potion entirely."

Harry swallowed thickly and nodded. He had a bad feeling about this.

He dipped the proffered cup into the lavender liquid and passed it to the headmaster. Dumbledore drank and stood for a moment… nothing happened…

Then, groaning, Dumbledore got to his knees. "Water," he rasped toward Harry.

"I'm sorry, Professor," Harry mumbled, filling the cup again and passing it to Dumbledore. Dumbledore drank it thirstily, then called out in anguish.

"Water," he rasped again, groaning in misery.

"Here," Harry said, his heart racing. "Here's water, Professor." He plunged the cup back into the potion and gave it to Dumbledore, who drank again and then curled up further. He groaned and cried into his hands, but Harry did not stop filling the cup. On and on this continued, Dumbledore's cries turning to screams of anguish.

"Professor, just one more sip!" Harry said, noticing the liquid had been entirely removed. "One last time, then we can leave!"

Dumbledore shook his head, looking absolutely pitiful. "Professor, please!" Harry cried, forcing the cup to his lips. Dumbledore drank and screamed yet again.

Harry dropped the cup and looked at Helga Hufflepuff's goblet. Sirius had told him not to grab horcruxes because they may contain a curse, but Harry didn't know how to break the curse and knew Dumbledore wasn't in a state to use magic at all. He lifted the cup and placed it in his pocket, before turning to the headmaster.

"Water," Dumbledore rasped again, crawling towards the water. Then Harry realized, with perfect clarity, the impossible trap Voldemort had set for anyone who dared steal his horcrux.

"Professor, no!" Harry shouted, using all his strength to pull Dumbledore into the boat. "Sirius has water, just wait a minute, we'll be back soon."

They flopped in the boat and Harry tapped his wand against the oars. He immediately grabbed Dumbledore's hands, which were reaching into the water. "Professor, please hold on. We're almost there."

The boat ride back felt longer than the one to the center. When Harry could see Sirius's form, he shouted. "Sirius! Conjure water - Dumbledore… the potion was poisonous! He needs water!"

"Damn it," Harry heard Sirius shout. "I can't, Harry. The cave must prohibit us from using magic. We need to get out of here."

Together, they hoisted Dumbledore out of the boat and pulled him out of the cavernous room and to the mouth of the cave. He was still moaning and crying out. "Hold tight, Harry," Sirius mumbled, and Harry felt the familiar sensation of being squeezed through a tube.

The trio landed once again in Hogsmeade. Harry and Dumbledore both toppled over. Sirius conjured water and poured it into Dumbledore's mouth. The headmaster gasped and reached his hand up for more.

After a few moments of spluttering, Dumbledore appeared to be gaining his strength. "Harry," he rasped, "did you get it?"

Harry pulled the goblet out of his pocket and held it up. Dumbledore eyes twinkled as Sirius helped him stand. "Brilliant, let's get back to the castle-"

"Dumbledore!" A woman shrieked nearby, approaching them. "The castle - Death Eaters! Minerva just sent word. Hurry!"

The three broke into a run. "Harry," Sirius started, holding out a hand. "Pass me the horcrux. I don't want the death eaters to pursue you if they know you have it."

Harry passed it to his dad, who shoved it in his robes and ran faster. When they reached the gates, Dumbledore ran on. Sirius grabbed Harry's arm and pulled him a different direction.

"Where are we going?" Harry asked, following his dad's lead.

"I think we need to hide, especially with what we're holding. I don't know that the Death Eaters here know what this is, but if they did, we would be dead in a moment." Sirius said, pulling Harry behind Hagrid's cabin and to the edge of the Forbidden Forest. "I'm going to destroy the horcrux now, before we run into any trouble."

He pulled the cup out of his robes and placed it on a rock nearby. Then, he grabbed the sword out of his bag, lifted it above his head and sent it crashing down on the goblet. Whereas previous horcruxes had engulfed into dark smoke, this one broke into shattered pieces and lay still.

Harry breathed heavily… "Sirius… what?"

"It…" Sirius started, looking shocked. "It was a fake. Someone must have… no way."

Before Harry could ask another question, they heard shouting from the top of the astronomy tower. Both rushed around Hagrid's cabin in time to see a flash of green light and a body - Dumbledore's body, falling.

"No!" Harry yelled, charging towards the castle. Sirius jumped forward and wrapped his arms around his son.

"Harry! It's not safe, we must stay here until -"

"Until you're found, dear cousin," a crazed, female voice rang out.

Sirius spun around, wand raised. Harry jumped to his right, doing the same. "Bellatrix," Sirius growled. Sirius shot a stunner, which she dodged effortlessly before disarming and stunning Harry. Harry, who hadn't been on guard, keeled over, feeling his head hit the hard earth. Bellatrix cackled and Sirius roared as he shot forth more spells.

The two were in an intense duel - Sirius stood in front of Harry in an attempt to prevent any misfirings from hitting him. However, Harry felt someone yank on his hair and pull him to a standing position. Lucius Malfoy stared at him with disdain. "Bella," he called out. "Take your time with Black, I'm going to move Potter to our cell."

Sirius turned around, shocked to see Lucius holding his son. His reflexes weren't quite fast enough, and the next thing he knew, he too was keeled over on the ground, angrily staring at Lucius as he ran towards the Hogwarts gate with Harry.

He heard Bellatrix's giggle as she grabbed his arm. "Don't worry dear cousin, you and your little boy will have plenty of time together where we're going."

Sirius eyed her angrily, but couldn't do or say anything as he felt her levitate him and run towards the gate, surely to aparate them somewhere.