Harry couldn't breathe.
It wasn't about fear. Nothing could breathe inside of Grimmauld Place. Oxygen had been sucked out soon after the door. The house was sealed. A trap.
A quick Bubble-Head Charm handled Harry's respiratory needs. It wasn't a common spell, but it wasn't exactly advanced magic. If someone went to the lengths of enchanting Grimmauld Place like this, they wouldn't stop at suffocating him. Something more was out there.
Harry walked to the main hall. He kept his wand ready and his senses sharp. He heard nothing. He saw nothing except Grimmauld Place's macabre decor. Where he walked on the carpet, dark dust puffed out. He stepped into the hallway.
Yellow eyes.
"Protego!"
Harry's shield formed an instant before a hoof struck. His shield was hit head-on. A barrier that could repel bullets trembled… and broke.
Harry was already moving back. The beast that attacked him tried to bite through his torso with powerful jaws. It missed. Harry had created distance too quickly for it to catch him.
Old habits came back. Harry scanned the threat in an instant.
Goat-like legs with cloven hooves and hair as coarse as metal. A golden mane started at the neck, but it was matted and dark in spots. A scaled tail flicked behind the beast's body, coming in and out of view in the dark hallway. Harry's mind screamed, Chimaera.
And yet, it was dead.
A jagged rift cut across its forehead and past its left eye. Its head had been caved in. It moved, walked, and hunted in a house devoid of air. This wasn't a living beast. Inferius.
Animating a human corpse was a challenge only the most powerful dark wizards could meet. To do it with an XXXXX Class Magical Beast was even more impressive than killing a Chimaera in the first place.
As the monstrosity charged, Harry met it with a lance of flames from his wand. But their intensity dropped before reaching his enemy. The embers that remained were smacked aside by the Chimaera's dexterous dragon tail, coated even in death with unburnable scales.
Magic didn't adhere to ordinary rules. If you conjured fire with the right spell, fire would always appear. But once you conjured it, if it had nothing to burn off of, it would inevitably go out. It was the same principle as putting out a magically-started fire with water. Inside Grimmauld Place, there was currently no air. Harry's best flames were no better than sparks.
He twirled his wand. The floor turned to ice. Harry shot wind into the monster's face, hindering its vision and pushing himself backwards along the frictionless ground. At the end of the hallway were two sets of stairs— one going down to the basement kitchen, the other climbing to the second floor.
Harry jumped off of the icy ground onto the ascending stairs. The Chimaera, chasing him with its vision hindered, was unable to change directions. It crashed down the stairs into the basement. Harry pulled his head back as a last-second swipe of its barbed tail nearly tore open his throat. He bounded up the stairs, taking advantage of the time he'd bought.
Harry could hear its steps behind him by the time he reached Grimmauld Place's drawing room. The portraits here had escaped the fate of Walburga Black. Perhaps they knew what had become of their ancestral home, because none of them spoke; they watched him in silence.
A Boggart Harry vaguely remembered the Order clearing out burst from the room's writing desk. For a moment there were two Harry's in the room.
"Riddikulus!"
The Boggart transformed into Dolores Umbridge wearing an 'I-Heart-Muggles!' t-shirt. She looked scandalized, immediately fleeing back into the writing desk.
Harry faced the door in time for the Chimaera to tear through the frame.
It had suffered no damage from a simple fall down the stairs. Even blasting it with an explosion was unlikely to stop it. Inferi hardly flinched from anything but fire.
Harry couldn't retreat. In the literal sense, Apparition and other forms of magical travel had been blocked. But even if they hadn't been, Harry wouldn't run. If this thing got loose the fallout wouldn't stop at a few lives. They were in the middle of Muggle London. Hundreds of non-magical civilians were as good as doomed, and the first Aurors on the scene would probably follow them. What Harry was facing was a true monster.
"Come on then," Harry said. "I guess we're doing this the hard way, you and I."
The Chimaera lunged at him.
Shielding was a waste of time and would only trap him on the defensive. Harry used a Banishment Charm on his own body to fire himself across the room. A Cushioning Charm cast on his landing spot kept him from breaking his bones against the wall.
Harry didn't waste the time that he'd earned himself. His wand chained spells together. Cutting Curses, Blasting Hexes, Bludgeoning Charms. He bombarded the beast as it charged him. His goal was to take at least one of its legs.
The most he managed was to leave gashes in its fur like the one that killed it. But this was no longer a living being. Cracking its skull wouldn't even slow it down.
It tried to bite him, and Harry rolled the opposite way. He heard the Chimaera's fangs grind through the wall he'd just been in front of. It kicked like a horse to catch Harry, but a well-timed blasting charm diverted the kick. He felt wind off of the hoof as it passed his head.
Fire came from Harry's wand again. This close, there was less time for the lack of air to weaken it. But the Chimaera's tail was in the way once again, its scales acting as the ultimate shield. Defense was turned to offense when that tail hit Harry in the chest and threw him across the room.
There hadn't been time for a cushioning charm, so Harry had opted for something faster. Three thick cushions shot from around the room to wedge underneath him. It still felt as if he might've sprained his chest when he hit the ground. Harry conjured a wall of iron that split the room in half, then ran through the last door available to him.
It was a conjoined bathroom. Distant memories flitted through his head as he traversed this house. He fled to this bathroom once in the middle of the night, when Voldemort's visions were too much for him to handle.
The bathroom's other door exited into a bedroom. Ginny and Hermione stayed here, if Harry remembered correctly. Without Order activity the room hadn't been renovated in the slightest. A glass cabinet displayed pickled fingers in what might have been an artistic array, a house elf head was mounted next to the thick curtains covering the room's only window, and a portrait of a sour-faced woman hung above the bed. Harry dropped and sat on the floor, not trusting the furniture not to be cursed. The portrait's eyes followed him.
"The house you were so proud of has been reduced to a trap. I guess it's not so grand anymore, huh?"
The portrait didn't respond to him, and Harry didn't taunt her further. He needed a plan.
Physical methods were as ineffective as Harry expected them to be. Right now, his Bubble-Head Charm was the only thing keeping him alive in this elaborate grave. Could he conjure another one around the Chimaera, using that to finally burn the monster?
Possibly. But it would be a risk. The charm took a mild amount of concentration to maintain. Harry was worried that if he used a second one, he'd lose the thing that was keeping him breathing.
The Chimaera Inferus was fast, persistent, and powerful to go with its resistances. By blocking his path Harry had earned himself time to think, but—
The ceiling broke above him.
Harry reacted without consciously thinking of a spell. He moved his wand and the drapes responded to his will, shooting out to grab his wrists. They pulled him out of the way as the Chimera broke into the room from the floor above with a brutal roar.
It had gone around the barrier! But how could it know exactly where he'd been hiding—
Almost by chance, Harry noticed something strange. The room's portrait hadn't said anything, and yet…
She was still looking at him.
Walburga had been burned while the rest were spared. They watched him like it was their only purpose. The portraits had been turned into a system of spies. They were part of the trap.
Harry obliterated the woman's portrait with a flick of his wand. The chimera came for him with its jaws gaping. He still didn't have a method to face it, so Harry chose to keep running.
The drapes he'd enchanted hurled him through the hole in the ceiling. He used the entrance the Chimaera created to escape it again, however temporary the reprieve was. Once they threw him, the drapes attacked the undead beast, binding it while it thrashed against them.
Fighting in Grimmauld Place was the worst possible battlefield. Outside, he would've been able to find a way to burn it. But taking the fight there would put innocent people into the path of danger. If only there was a way to communicate with the Order, so they could evacuate the area ahead of time—
As sounds of tearing cloth rang out from the floor below, Harry noticed his surroundings. This was what would be… or had been his room. The one that he shared with Ron. There was a portrait here, too.
Except it was nothing but a blank background.
"Phineas!" Harry said. "I know you can hear me! You glorious slimy bastard, of course they wouldn't have caught you!"
The frame stayed empty.
"Phineas!"
A few black hairs poked into view in the bottom corner from out of frame. "No, no one here by that name. No Phineases at all. There are no portraits in this house, can't you tell? They've all been enchanted. Turned into… something else."
The Chimera's tail came into sight, decorated with the torn remains of the curtains Harry recruited. The tail wrapped around one of the beds and started dragging the rest of the Chimaera into the room.
"There's no time!" Harry said. "I'm not telling you to stay here, and you better not get enchanted by anyone before you deliver a message to Dumbledore! Tell him Grimmauld Place was a trap! I need the street evacuated by any means necessary!"
"...Why should I?"
"Because whoever did this isn't the only one who can affect portraits. If you leave out any part of what I just said, not even Dumbledore can stop me from tearing your frame out of his office and turning it into House Elf toilet paper!"
"Going!" Phineas said.
The bit of his head that had crept into frame vanished, running back to the Headmaster's office. Harry prayed that Dumbledore wouldn't be out on business.
He faced the monster in front of him. Its hooves weren't suited to climbing, but it had managed to heave itself back onto the third floor all the same. Harry tightened his hold on his wand. He smiled, his heart pumping the way it did whenever he went for a wild stunt on his broom.
"It's just us again," Harry said. "Let's do this."
The Chimaera charged, and this time he stood his ground.
Buying time was a dangerous game. Harry used physical spells to divert the blows that were meant for him. He knocked hooves and fangs off course and deflected the monster's tail when it crashed down at his head.
Keeping his Bubble-Head Charm up was yet another thing tugging on his attention. Inevitably, he made mistakes. Blows he meant to turn away clipped him, and bites intended to snap his neck left shallow passing cuts. Mistakes were fine, as long as they stayed minor.
When Harry couldn't dodge an attack, he thought outside of the box. Sometimes that meant a well-timed Cushioning Charm and allowing his body to be thrown. At other times he fought back. Once, he used a Blasting Charm to send the Chimaera through the ceiling. It hadn't been hurt, but that bought him a full minute.
Harry had no way of knowing when the Order would get his message. He should have communicated his plan better, but who would have expected something like this? Voldemort had no way of knowing that the Horcrux from the cave had ended up here. Sirius, the sole man who could access Grimmauld Place, had no idea about the fate of Kreacher or what the home had been turned into. Harry was just glad that he came alone. If he had to protect someone this whole time, it would not have gone as well as it had.
All the same, by the time the battling pair had fought through the master bedroom, Harry was bleeding in a dozen places. His robes had been ripped and his chest was screaming at him. If this went on much longer he would have to teach from a wheelchair.
He couldn't even reliably judge time. Maybe it had been half an hour since Phineas relayed his message and the Order already swept into action. Or it had been five minutes and Dumbledore was out to lunch. He was helpless to tell.
Harry absorbed another swipe that threw him back. He was knocked up the last flight of stairs, hitting one of the two doors on the top floor. It was Regulus Black's bedroom, with Sirius's old room opposite it. The Chimaera jumped the stairs in one go. Harry ducked. He managed to roll backwards as the door to Regulus's room was torn off of its hinges.
The space decorated the way Regulus had it when he died. That included a Slytherin bedspread and posters of exotic snakes. Even the wallpaper was Slytherin-themed. Maybe because it was on the top floor, this room had more natural light than anywhere else in the house. The curtains were pulled back, sunlight streaming in. The better Harry could see it the uglier the Chimaera became. In addition to the wound that killed it, Harry's spells had torn away bits of flesh and sinew all over its body, making it look like the half-finished meal of a vulture flock.
The Chimaera roared right in his face. Undeath hadn't robbed it of all its habits. It still felt like an apex predator. Harry decided that he couldn't delay any longer.
He hit the window behind him with a powerful Blasting Curse. Instead of shattering, the window barely cracked.
It was as if it had been reinforced with a powerful charm. Yet another layer of defenses. This was the most potent trap Harry had ever encountered. Where did it come from?
He didn't have time to think, only to act. The Chimaera managed to stamp its hoof on his chest. Harry stopped the momentum to keep it from breaking the rest of his ribs, but the monster still leveraged its weight, pinning him down. He couldn't move!
He sent another blasting curse at the window behind him. He managed to shatter the glass this time… but nothing entered. Whatever had been done to remove the air in Grimmauld Place blocked anything from flowing in.
As if sensing his failure, the Chimera tried to bite his head off.
Harry had nothing to lose. He canceled his Bubble-Head Charm.
He immediately felt the primal panic that comes with failing to breathe. Harry controlled it. He conjured the biggest Bubble-Head Charm he could manage over the Chimaera's whole head.
As its jaws snapped down, Harry thought of a happy memory. He pictured the faces of his students leaving his first class— engaged and thoughtful because of the points he raised. A shape that looked similar to the Chimaera's legs, only translucent blue instead of furry and bloody, took shape, wedging the Chimaera's jaws open.
If this didn't work, Harry would suffocate. If he lasted that long.
"Incendio!"
Harry put his arm halfway down the undead beast's slimy gullet. One of its fangs nicked his arm and pierced a few centimeters deep. Harry gritted his teeth and poured out every bit of fire he could muster.
It was incomparable to any of his attacks so far. The only place in all of Grimmauld Place receiving air was the Chimaera's insides, and that's what Harry torched with a continuous jet of flames. He refused to stop until the Chimaera keeled over. His lungs were burning to the point that his eyes watered, but Harry replaced his own Bubble-Head Charm just as his consciousness was starting to flicker.
When the Chimaera gave its last twitch, he raised a fist in triumph.
O-O-O
"I swear it should've been empty!" Sirius said. "Without the ring I gave Harry, no one could get in! My family were terrible but their wards were top-notch!"
"It's okay Sirius," James said. "You couldn't have known. Harry will be fine."
James was the one offering reassurances, but he was also the first to barge through Grimmauld Place's front door the moment Sturgis Podmore said, "All clear!"
James, Sirius, Sturgis, and Kingsley made up the response team the Order scrambled together. Kingsley was evacuating the surroundings. He'd falsified a misuse of magic report with James's help, allowing him to treat this as standard Auror work.
The other three were the rescue team. Harry never specified what kind of trap it had been, but the urgency was communicated loud and clear. James and Sirius were two of the best wands the Order had, while Sturgis was their ticket inside.
James burst through the door, Sirius hot on his heels and Sturgis a bit behind that. They could feel the outside air reentering the house along with them. "Merlin, a Vacuum Ward?" Sturgis said. "I knew this felt advanced when I was breaking it, but an array like that costs thousands of galleons. They don't last long before breaking down, either. It must've been put up recently."
"Shit," Sirius said.
He had walked far enough to see the dining room and was staring at Kreacher's body. "You always were a shit elf, but if I find who did this…"
"There was a fight here."
James was crouching with a hand on the hallway's floor. He traced a series of dents. When James lifted his fingers, they came away with a sparkly residue on them, reminiscent of a frosty morning.
"I'm going upstairs."
"Hold up!" Sirius said. "I'm right behind you!"
The higher they climbed, the worse the damage got. Holes opened in the ceiling and craters were visible on the walls. They spotted blood and bits of white fur scattered around, sometimes still attached to clumps of meat.
With every room James moved faster. He sprinted up the last set of stairs. Sirius and Sturgis struggled to keep up, until James abruptly stopped.
Sirius saw why as he reached the threshold of Regulus' old room. They'd found Harry.
He was cut and bruised, but his face didn't have any damage except a vague singing. His hair looked slightly charred in places. He canceled a Bubble-Head Charm when he saw them and realized air had returned. He looked grim, perched atop a beastly corpse that was blackened from the inside out. The mimicry of life had faded from the monster's cloudy yellow eyes.
"Somebody got me good today," Harry said. "I intend to find out who."