The Lost Realm: The Hidden Horizon

The First Hallway

Hogwarts had never looked so dangerous.

Harry stood outside the gates at midnight, rain soaking through his Polyjuice disguise. He looked like a middle-aged wizard with a grey beard and dull brown eyes – one of the many anonymous Ministry workers who now patrolled the castle. Beside him, Draco wore the face of a young witch with mousy hair and nervous hands. Hermione had brewed the potion perfectly. They had four hours before it wore off.

Ron and Ginny waited in Hogsmeade, under Invisibility Cloaks, ready to cause a distraction if needed. Hermione had stayed behind to guard Grimmauld Place. None of them liked the plan. But none of them had a better one.

"Remember," Draco whispered, his voice strange coming from a woman's face. "We don't speak to anyone. We don't look at anyone. We go straight to the second-floor bathroom."

Harry nodded. "Follow my lead."

They walked through the gates. The wards hummed against Harry's skin but did not reject him. The Polyjuice fooled them – barely. Harry could feel the black thread on his wrist vibrating, as if it recognized this place. As if it had been here before.

The castle corridors were empty. It was summer break, but Yaxley had stationed Aurors everywhere. Every few steps, Harry saw a patrol – two wands, cold eyes, grey uniforms with the new Ministry seal: a serpent eating its own tail.

"Symbol of endless power," Draco muttered. "My father had that symbol on his study door."

They climbed staircases that moved too slowly, passed portraits that watched them with suspicion. The Fat Lady was gone. Her portrait hole was now guarded by a troll in armour. Harry's stomach turned. This was not his Hogwarts. This was a prison.

Finally – the second-floor corridor. The entrance to the girls' bathroom. The place where, years ago, Hermione had brewed Polyjuice and Ron had almost died from a bad hair.

Harry pushed the door open.

Moaning Myrtle floated above the sinks, crying into her hands. When she saw them, she stopped. Her transparent face twisted into something ugly.

"New patrol," she hissed. "You're not supposed to be here. The other one said no one comes in anymore. The other one said I'd be thrown into the lake if I let anyone through."

"What other one?" Harry asked.

Myrtle giggled – a horrible, wet sound. "The tall one. The one with no nose. Oh wait – that was the old one. This new one has a nose. But his eyes are dead. Like a shark."

Yaxley. He had been here already.

"Did he go through?" Draco demanded.

Myrtle pointed to the third sink from the left. The taps were normal – except one. The middle tap had a serpent engraved on it. Harry knew that symbol. Parseltongue.

"He spoke to it," Myrtle whispered. "Hissed something. Then the sink opened. He went down. Hours ago. He hasn't come back."

Harry looked at Draco. Draco looked at the tap.

"I don't speak Parseltongue," Draco said. "But you do."

Harry stepped forward. The black thread on his wrist grew warm. He leaned close to the serpent tap and hissed: "Open."

The sink trembled. Then it slid downward, revealing a dark hole – not a pipe, but a stone staircase. The stairs descended into absolute darkness.

"Lumos," Harry whispered. His wand lit the first few steps. The walls were covered in ancient carvings: serpents, lions, badgers, ravens – the four Hogwarts houses. But the serpents were largest. And their eyes were made of real emeralds that glowed green.

"I'll go first," Harry said.

"No," Draco said. "Dumbledore said together. That's the only way."

They stepped onto the first stair at the same time.

The moment their feet touched the stone, the stairs vanished. Not broke – vanished. Harry and Draco fell.

They landed hard on cold dirt, twenty feet below. Harry's ankle screamed. Draco's borrowed witch-face scraped against a rock. Above them, the staircase had disappeared completely. They were in a narrow tunnel, lit by torches that had no flame – only floating orbs of green light.

"Brilliant," Draco coughed. "We're underground. In Hogwarts. With no way back."

"We don't need a way back," Harry said, standing. "We need a way forward."

The tunnel led to a door. Not a grand door – a wooden door, old and rotting, covered in warning signs. Harry read the first one: "Abandon all hope, ye who enter here."

"Someone read too much Muggle poetry," Draco muttered.

The second sign was handwritten in dried blood: "Salazar's heart lies here. Only the worthy may touch it."

"The first Horcrux," Harry said. "It's not a diary or a locket. It's his actual heart. Preserved in magic."

Draco went pale. "That's disgusting."

"Dark magic usually is."

Harry reached for the door handle. The black thread on his wrist shot out like a whip, wrapping around the handle and turning it before Harry's fingers touched it. The door swung open.

Inside was a room made entirely of glass. Floor, ceiling, walls – all glass. And in the center, floating in midair, was a human heart. It was still beating. Still pumping. But the blood inside it was black, and the veins were made of shadow.

"The heart of Salazar Slytherin," said a voice.

Harry spun around.

A man stood in the corner of the glass room. Tall. Bald. Eyes like dead fish. Corban Yaxley wore fine black robes and held a wand made of silver. He was smiling.

"Potter," Yaxley said. "Or whoever you are under that Polyjuice. Did you think I wouldn't feel you enter? The Shadow Weaver's mark broadcasts your location like a beacon. I've been waiting for you."

Harry dropped his disguise. There was no point hiding. His green eyes met Yaxley's dead ones.

"Malfoy," Yaxley said, nodding at Draco's borrowed face. "You can drop yours too. I'd recognize that coward's posture anywhere."

Draco shed his disguise. His grey eyes were hard. "You worked for my father."

"I worked with your father," Yaxley corrected. "There's a difference. Lucius was a fool who thought blood purity could win wars. I know better. Wars are won with fear. And I have made this entire country afraid."

He gestured to the beating heart. "This is the final piece. With Slytherin's heart, I can create a curse that will kill anyone who disobeys me. Not just death – erasure. They will never have existed. Their parents won't remember them. Their children will never be born."

Harry felt the black thread pulse violently. "You're mad."

"No," Yaxley said calmly. "I'm efficient."

He raised his silver wand toward the heart.

The glass room exploded.

Not from a spell – from Harry. The black thread on his wrist shot out like a hundred tiny needles, shattering every glass surface. Shards flew everywhere. Yaxley threw up a shield, but the shards were not aimed at him. They were aimed at the heart.

Slytherin's heart screamed.

It was a terrible sound – not human, but not animal. The scream of a thousand-year-old evil waking up. The black blood inside the heart burst out, flooding the glass floor. Harry grabbed Draco's arm.

"Run!" Harry shouted.

But there was nowhere to run. The floor was gone. The walls were gone. They were standing on a lake of black blood, and the heart was sinking into it like a stone.

Yaxley laughed. "You've destroyed it! You fool – you've destroyed the very thing I came for!"

"No," Draco said, his voice shaking. "He didn't destroy it. He woke it."

From the black blood rose a figure. Tall. Wearing green robes. A face like a snake – but not Voldemort. Older. Sharper. Salazar Slytherin himself, or the ghost of him, made of shadow and blood and rage.

"Who dares disturb my rest?" the figure hissed.

Harry stepped forward. The black thread on his wrist reached toward Slytherin's ghost like a child reaching for a parent.

"I do," Harry said. "And I'm not afraid of you."

Slytherin's ghost laughed. "Then you are a fool."

"No," Harry said. "I'm the Master of Death. And you're just a man who couldn't let go."

He raised his hand – the hand with the black thread – and touched Slytherin's heart.