Fire And Ice - Yin and Yang (Harry Potter fanfiction)

The door on the third floor - and what's behind it

"What are you doing here?", Azalea burst out.

"The ghost led us here", Periwinkle defended herself and motioned to the bloody woman, who was floating in front of the closed door.

"We came to tell you that Dumbledore left", said Hermione hurriedly. "And the thief is still here, apparently Madam Pomfrey has been trying to heal his frozen shoulder."

Periwinkle's eyes went wide.

"But if Dumbledore left-" started Ron.

"Then we need to get the stone now", Azalea finished and looked out of the window. "It's almost dinner time. Everyone will be in the Great Hall. This is our chance."
She walked toward the door and the ghost disappeared behind it.

Ron, Hermione and Periwinkle pulled out their wands.

"You ready?", asked Azalea with her wand pointed at the door.

"Definitely", said Ron grimly.

"Alohomora."

They closed the door behind them and found ahead a humongous dog with three heads sleeping in the center of the room. Beside it, a harp played a tune on its own.

"We're too late!", whispered Hermione. "The thief's already been here!"

"The ghost is gone", said Periwinkle perplexed and turned around in a circle.

"Never mind the ghost, we need to find the door", said Azalea urgently and went to the left to check the shadows. The others split up, running their hands across the stone walls.

But there was no door.

"Maybe its hidden-", started Periwinkle, when a huge head appeared out of nowhere. Snarling and slobbering everywhere, the huge dog's head snapped at her. Its teeth missed her by inches as ducked.

"Guys!", she yelled, "the harp! It stopped!"

Two more heads appeared, all attached to the same neck. Their black eyes blazed down at them and they opened their jaws, ready to attack.

"We need music!", shouted Ron in panic. "Sing something!"

"I can't sing!", screamed Hermione.

Azalea opened her mouth and- sang the first tune coming into her mind.
"Silent night", she croaked out, "holy night."

Ron, Periwinkle and Hermione stared at her as if she'd lost her mind.

"All is calm-", Azalea drew a breath, "- all is bright."

I can't remember the rest, she thought in panic and hurriedly motioned for Periwinkle to continue.

"Please don't eat us, for Hagrid's sake", Periwinkle stammered out of tune. "We'd only give you a stomach ache."

The dog heads yawned widely and started to lower themselves onto the floor.

"Sleep in heavenly peeeeeeace-"
Periwinkle moved towards the dog, checking the walls behind it again for a door.
"Sleeeep in heaaaaavenly peaaaace."

She drew a breath.
"Ron!", she whispered, "your turn!"

The middle dog head started growling and the redhead started singing with a pale face.

"S-Silent night, holy night.
We all q-quake, at the sight-"

He stepped around a head, checking the other corner for a door.
"Slobber streams from dog heads afar."