River hurried back from the library with an armful of books. One fell from the pile as she passed the kitchen and she swore as she had to stop to pick it up. She wanted to get back to the console room before the Doctor woke up, in case he wasn't there. What if she hadn't fastened the handcuffs properly? What if there were other means of attack?
She ran down the remainder of the corridor, and breathed a sigh of half-relief when she saw the Doctor still there when she entered the console room. He was awake, tugging at the handcuffs and staring at the closed exterior doors. He didn't even look at River until she dropped the books heavily onto the edge of the console.
“River, let me go.”
She shook her head. “I can't.”
“River, I can hear them.” He pulled at his restraints. “Why are you doing this?”
She crouched down in front of him. “There's nobody outside, my love. Nobody that you want to see.” She knew he wouldn't believe her, but she still hoped that enough lucidity from herself would mean some of it rubbed off onto her husband. She touched his hair and winced when he pulled away from her. “Gallifrey's gone. The Time Lords are gone.”
“Then why can I hear them?” he demanded.
River stood up and looked down at him sadly. “It's a Siren. I told you before and you wouldn't listen to me.”
“They're extinct,” said the Doctor calmly. “I was there when the last one died.”
“Well, there's one outside and I don't think it got the extinction memo.”
“You,” he said, “are not a Time Lord. You can't even hear them.”
“And that's the only reason you're still alive.”
The Doctor opened his mouth to say something in reply and then stopped, turned his gaze back to the doors. “How did you get here? I thought you were dead.”
River shuddered. “What's it doing?”
The Doctor moved as much as he could, straining to get away from the railing. “Can't you see her? River, you have to let me go.”
“River, stop playing games!”
River nodded and took a step back. “There's no point to this conversation, is there?” She turned to the console, picked up one of the books she'd found in the library. “I promise I'll let you go when I've found a way to get rid of it.”
The Doctor slumped against the railing and continued to stare at the doorway.
In the beginning, Rassilon, Omega, and...
...when the star collapsed...
...but the Great Vampire fled, and...
...but none could resist the Sirens, who sang to the wishes in their hearts...
River read on, taking care not to rush in case she missed some vital detail. The brief paragraphs of dry history didn't give any answer. She picked up the next book and flicked through the pages.
“River, listen to me. Something isn't right here. You're not yourself.”
She read on, trying not to listen to the Doctor.
“Just let me go and we'll talk about it. The people outside can help you, even if I can't.”
River closed the book. “You said there was someone in the TARDIS. Where did she go?”
“Outside,” he said, as though talking to a child. “Back to the others.”
“Who was she?”
“Why, are you jealous? Is that what this is about?”
“I don't do jealousy. You know that.” She sat down next to him. “I'm only trying to help you. I know you can't understand that right now, but-”
“Don't patronise me,” he said with sudden anger. River flinched away automatically.
He sat quiet for a moment and then said “I don't know why I ever thought a human would be enough.” It was a casual statement of fact and it hit River like a knife in her stomach. “That's all you are, River, all you'll ever be.”
“I'm the child of the TARDIS,” she said, more defensively than she'd have liked.
“You gave up your regenerations for a man you'd only just met. A man you'd tried to kill. That was stupid.”
“I did it because you saved me from destiny,” said River. “And I've never regretted it, not once.”
“Well, you should. I regret it every day.”
“You don't mean that.”
The Doctor looked at her, his expression such a close parody of affection. “We could have had forever.”
River stood up again. “I'll let you go on one condition.”
“Tell me how to kill a Siren.”
The Doctor sighed. “Not that again.” He leaned forwards as far as the handcuffs would allow. “Do you really think it would let me tell you, if it was real?” He shrugged. “Just run away, that's how all the heroes of legend did it.”
River looked at the shuddering time-rotor. They were trapped in a knot of space-time and without the Doctor's help there was no way to escape. Even the sirens of Earth knew to stay where ships might run aground. “What else?” she asked.
The Doctor didn't answer.
River stood in front of the console. “Oh, I hate having to do this. Activate emergency voice interface.” The air rippled and she found that she was looking at herself. “Oh, how flattering,” she said bitterly. “How do I kill a Siren?”
“Sirens cannot be killed.”
“Then how do we save the Doctor?”
The hologram flickered. “The call of true love.”
River clenched her fists at her sides. “I don't think love is helping much here.”
“And that says all you need to know, doesn't it?” said the Doctor from the floor. “Switch that thing off, you're wasting power.”
“Which means it probably does know the answer,” said River. “What's the call of true love?”
“A colloquial name for the song of a TARDIS.”
“How do I make you sing?”
The hologram flickered again and finally disappeared. That wasn't good. That probably meant it was starting to affect the TARDIS as well.
River took a deep breath and addressed the console. “Listen to me. I know how much the Doctor means to you. I will never, ever take him from you, but that thing out there will. Tell me what to do. Please.” She realised she was crying. She wiped her face with the back of her hand. “Fight it, I know you can.” River leaned on the console, and closed her eyes. “Be the pilot for once. I'm all yours.” River felt her hands move, forced herself to relax and let them caress the controls.
And the TARDIS sang.
A shrieking wail pierced the air and the doors flew open. Something hideous and deadly writhed in the buckled space outside. The insistent, pulsing beat from the TARDIS rose in volume, became an otherworldly melody. Everything shook. Finally the doors slammed shut and the noise from outside suddenly stopped.
River let go of the console. “Doctor?”
“River,” he said, calm and quiet. “It's okay, it's gone.”
Hesitantly she turned to him. “Are you sure?”
“I can't hear it anymore.”
River uncuffed him and helped him to his feet, hugging him close when he stumbled into her. “We have to get out of here,” she told him, sitting him down in the chair.
“But there's no vortex here. Where will we end up?”
“Two inches to the left. It's a bit of a fault but it's about to save our lives. We can ride the spatial curves out if we get the speed right.” He stood and staggered to the controls. “You'll have to help,” he said, not quite meeting her gaze.
River realised that he hadn't looked at her since the Siren had fled.
She was putting the books back on the shelves when the Doctor entered the library.
“How are you feeling?” she asked, businesslike.
“Better.” He cleared his throat. “River, those things I said...”
“Do you want me to lie?”
“Don't you dare.”
He stepped close to her, took her hands. “I am so sorry.”
“I'd have said worse if it was me,” she said lightly.
He smiled a little at that. “Really?”
“Oh, I think the most awful things about you sometimes. And then there's your performance in bed.” She shrugged. “I knew those things anyway. Whatever happens I'll die before you. I can't expect you not to be bitter about that.”
“Everyone dies, River.”
“Except you.” She pushed his hair across his forehead. “You just go on and on, don't you?”
“Do you really not regret it? Giving me your lives?”
“I wouldn't want to live forever if it meant I never knew you.”
“That's both romantic and disturbing,” said the Doctor.
“Turns you on, doesn't it?”
River smiled and pulled him closer. “Kiss and make up?”
“I thought you'd never ask.”