"Ugh, my head…"
The world slowly swam into focus as Oleandra's eyes fluttered open. She rubbed at her aching jaw, struggling to recall what had happened last… and then she froze, at last noticing the ghostly face hovering not two inches from her own.
"Gah!" Oleandra yelped. "What the Hel!?"
"Oh, you're not dead," said Moaning Myrtle, sounding strangely disappointed as she slipped out of sight through a wall. "I thought your twin sister had finished you off— last time you fought here, you nearly drowned her."
Oleandra looked around her wildly.
She was no longer in the Headmaster's office, but in a toilet cubicle, perched rather awkwardly on a loo with the lid down. She glanced down; the black-gemmed ring was back on her finger, and a shimmer of silvery fabric lay across her lap; the Invisibility Cloak, which she immediately sent back into her Quick-Change Charm's storage space in exchange for her cardigan with a wave of her hand. Still feeling woozy, she rose unsteadily and pushed the door open, only to find herself in Moaning Myrtle's unmistakeable bathroom, the entrance to the Chamber of Secrets.
"If you're wondering where your sister went," Myrtle went on, pretending to swim through the floor as if she were a Land Shark, "she went through that mirror and never came back out."
Oleandra looked up. Myrtle was pointing at the mirror, where the sigil she had used to awaken her reflection still lingered. Without saying a word, she stepped closer, laid her palm against it, and closed her eyes.
A second set of memories flooded into her mind. She saw herself disappearing under the Invisibility Cloak, taking the moving stairs to Snape's office, talking to Dumbledore's portrait… and then punching herself. She gingerly massaged her jaw. She had to admit; she had a mean right hook.
Oleandra closed her eyes and tried to remember what had happened afterwards.
The mirror clone had prised the ring from her finger and cracked the stone with Gryffindor's sword. A roiling mass of black smoke spewed forth, but instead of dissipating, it spiralled down into the crystal phial she had just unstoppered. She placed the phial on Snape's desk as instructed, spoke further with Dumbledore, then fed the comatose Snape a Wideye Potion from his personal store before fleeing, an unconscious Oleandra under her arm.
"Hullo?" Moaning Myrtle said irritably. "Are you even listening to me?"
Oleandra ignored her.
"That phial…" Oleandra muttered to herself. "It looked exactly like the one Loki dangled in front of me!"
She was at a loss. Why in the world was Dumbledore going out of his way to preserve You-Know-Who's soul fragments instead of simply destroying them? She couldn't fathom why he would do such a thing.
A vivid image of an ornately decorated room suddenly flashed before her mind's eye.
"I believe you'll find what you seek in my Pensieve," Dumbledore's portrait had told the Mirror Clone. "The location of the Map Room… Hogwarts's Nexus, as you so aptly put it."
Oleandra's eye flew open. So, her trip to the Headmaster's Office hadn't been in vain after all!
Following the calamity that collapsed much of the underground passages and catacombs beneath the castle, the Map Room had become physically inaccessible; the only way to reach it was to Apparate directly there, into a blind spot in the Anti-Disapparition Jinx that covered the grounds. To Apparate, though, one needed a clear mental image of the destination… which Oleandra now possessed, courtesy of her clone dunking her head in Dumbledore's Pensieve!
"Fine, ignore me, for all I care!" Moaning Myrtle screeched. "I hope you kill each other, and then you'll see how much it hurts your feelings when the living don't give you the time of day!"
Oleandra frowned. Blank spots marred her memories.
Towards the end, Dumbledore and the clone had shared a few words, but she could not make them out, and Dumbledore's face had even gone all fuzzy, rendering it impossible to read his lips. This time, no magical glitches could serve as an excuse; clearly, the clone had deliberately taken great care to hide that final conversation from her.
And yet, that was impossible: the magic should not have allowed it.
Oleandra's fingers brushed against her wand. She was tempted to shatter the mirror that housed her clone, and yet… the Reflection Doppelganger had still saved her by going against her will and cleansing the ring that was poisoning her mind.
"To the Map Room, I suppose…" Oleandra sighed, drawing her wand.
She had not learned to Disapparate properly, but she had absorbed the powers of the Diricawl; she turned on the spot and vanished in a swirl of blue feathers.