Amy was the first out the door, and she turned the corner into the bedroom. "Mels? You home?"
"Living room!" Mels called back.
"There you are!" Amy came in the room. "Look, I thought about what you said, and it sounded like something the Doctor would be interested in, so I gave him a call. Didn't expect him to land in your apartment, though. Sorry about that."
Mels, lounging indolently on the couch, gave a one-shoulder shrug. "S'cool. I didn't like the linoleum anyway."
"Oh, it'll be fine when we leave." The Doctor emerged from the TARDIS, followed closely by Rory, a cheerful smile on his face.
Melody Pond smiled. "You said he was funny. You never said he was hot." She stood and walked up to him, adjusted his bowtie. "Love the bowtie."
His eyes widened and his eyes flicked over to Amy. "See?" he crowed. "Bowties are cool!" Amy shook her head, and he returned his attention to Mels. "Now," he said, abruptly serious. "Who are you?"
"Doctor!" Amy objected. "This is my sister, Mels. I told you about her. Did you forget again?"
"I remember, Amelia," he responded, searching Mel's gaze. "But she knows things she couldn't. Referencing things four hundred years in my past. She told you, specifically to get me to come. Now that's interesting. That's very interesting, because I've never seen her before. So. Who are you?"
Mels smiled and wandered away. "I was hoping you'd recognize me. But I suppose it's to be expected. I was a few shades lighter and considerably more blond the last time we met."
"Mels-" Amy began.
"Not now, Amy," Melody said dreamily as she pulled down a particularly thick book from the bookshelf. "I have to kill the Doctor."
"What?"
"What?"
"What?"
The incredulous phrase was mimicked by three voices at once. Melody ignored them all and opened the book to reveal an old revolver. She pulled it out and pointed it at the Doctor, dropping the book and kicking it away.
"Mels!" Rory cried.
"Mels, stop!" Amy begged.
The Doctor stood there calmly and stared down the barrel of the gun. "Who are you?" he asked quietly.
"Well, that's the question, isn't it? I'm the lover you never had."
"Mels-" Amy began, but the Doctor cut her off with a hand gesture.
"Who are you, Melody Pond?" the Doctor asked with a piercing gaze. "I've never met you before."
"Oh," Mels said, pacing a step closer. "That's where you're wrong. You've danced with me, and laughed with me, and run with me. We hung together on an impossible planet over a black hole and faced down the devil. We wandered a planet of mushrooms, poking at enormous spores."
"No…" the Doctor murmured, his eyes huge.
"Yes!" Melody's eyes were burning pits. "We fired a rocket at ten downing street, and turned Margaret Slitheen into an egg."
"It's impossible!"
"I don't think you know what that word means, Doctor." She spat his name as if it were an insult.
"You can't be…."
She paced a step closer. "Who am I, Doctor?"
"No!" the Doctor cried, taking a half-step backwards, and Melody flowed forward to match him. "No, that wasn't you! You weren't there!"
"But I was." Her gun still trained between his hearts. "Time changes everyone."
"Not like this." His eyes raked up and down her form. She was, once again, twenty six. She wondered if he saw the irony.
"You do," she reminded him. "Who am I, Doctor?"
"You're not," he said stubbornly.
"I am," she countered.
He stared at her, hopelessly lost. Fear and longing swirled in his eyes as he tried to accept the truth she was presenting him with. Rose Tyler was dead. Lost in the explosion in Pete's World.
Her gaze softened, filled with love. But the gun. It was aimed straight at his chest, and it didn't waver.
"What's the first word you ever said to me, Doctor? The first word. Down in that basement of Hendricks. Surrounded by shopkeep dummies. One word. Just one. What was it?" she spoke softly. Sweetly. As if to a lover, reminiscing fond memories.
His jaw worked; he swallowed convulsively. He looked away from her, looked back. Finally, he spoke. "Run."
"Yes." She smiled, and it was like the sun coming up after a long night. "Run."
"How is it-" he began to ask, but she cut him off.
"What is my name, Doctor?" her tone was harsh again, unyielding. And her finger began to tighten on the trigger.
"What?" he asked dumbly.
"My name."
"…Rose Tyler."
And like that, the spell was broken.
"Oh, god!" Mels choked, lowering the gun with an effort of will and stumbling backwards. "Oh my god!"
"Rose-" The Doctor said, moving towards her.
"No!" The gun came up, stopping him in his tracks.
The Doctor raised his hands and slowly backed off. The gun was shaking, as she fought to point it elsewhere, but her finger was tightening inexorably on the trigger.
"Please," the Doctor begged, his whole body tilted towards her, even as his feet remained planted. "Please...don't do this."
"I don't want to!" she cried, but the gun steadied in her hand, still aimed right at his hearts.
"Please! Please, Rose, Mels, whoever. Please...come back to me." he begged her, stopping just short of dropping to his knees.
The tableau froze as Melody held the Doctor at bay with a gun. Amy and Rory watched helplessly as the Doctor begged. The gun dropped, and Mels stared at the Doctor with a look of such complete longing that it hurt to watch.
The Doctor slid one foot forward the tiniest amount. "Rose-"
"I love you," she said. Then she put the gun under her chin and pulled the trigger.
"No!" The Doctor dashed forward, somehow managing to catch her before she hit the ground.
"Mels!" Amy cried, rushing to her sister's side.
"No, no..." Rory mumbled, collapsing next to his wife.
"Oh, my Rose..." The Doctor whimpered brokenly, hovering a hand over her face as if he wanted to touch her, but dare not. He settled on wrapping both arms around her back and curling over her.
"Oh my god, look!" Rory cried, pointing at the ruined mess at the top of Mels' head.
When Amy and the Doctor looked, there was just a small cut, which healed rapidly and vanished.
"What?" Amy asked, as a soft golden glow began to seep from Melody's pores.
The Doctor put Melody down and grabbed each of them by their arms. "Over here," he urged.
"But, Doctor-" Rory protested, pointing to Melody who was almost obscured by the strange light.
"I know what's happening, and she'll be fine. Trust me."
"What is happening?" Amy asked.
"Regeneration."
The golden light suddenly increased in intensity until it peaked, rushing out in a blinding wave of power that the three observers were forced to turn their gazes away from. When they looked back, the woman they knew as River Song had taken the place of Melody Pond.
"That's...regeneration?" Rory asked. "Has she always been able to do that?"
"No." The Doctor moved quickly to Melody's side and placed both hands at her temples. He stared blankly down at her face while he delicately probed her mind. "Rose...River. Why did you have to do that?" he whispered, dropping his hands. "The conditioning is set now. If you'd let me in before you regenerated..." he bowed his head momentarily. Then he shifted and slid his arms under her, hefting her into his arms. "Rory, open the door," he said as he stood, gesturing with his head at the TARDIS.
"But, Doctor...she's River," Rory objected, staring open mouthed.
"Yes, Rory," The Doctor said with exaggerated patience, standing outside the TARDIS. "Now. Open the doors."
"...right."
Rory opened the doors, and the Doctor swept inside, his companions immediately dropping off his radar.
"Oh, no you don't!" Amy said, storming after him.
The Doctor led them deep into the bowels of the ship, down stairs and through corridors. He stopped before an unmarked door, which slid open. Amy and Rory hovered at the door uncertainly while the Doctor laid Melody in the exact center of the completely white room. Then he joined his companions and the door slid shut, instantly becoming transparent. The Doctor stared in at the motionless form for a long moment. Then he turned and went back to the console.