"Hey, who turned out the lights?" Zombie Dave called as he came ever closer, and River pulled out her gun, pointing it at the wall and creating a hole. "This way, quickly. Move!" She ordered, pushing Teresa ahead.
They all ran through, and the process repeated until River cut through into another Rotunda and she called: "OK, we've got a clear spot. In, in, in! Right in the centre. In the middle of the light, quickly. Don't let your shadows cross. Doctor."
"I'm doing it." He replied as he soniced around, and River muttered: "There's no lights here. Sunset's coming. We can't stay long."
As everyone else sank down for a rest, Teresa joined her as she asked the Doctor: "Have you found a live one?"
"Maybe." The Doctor muttered. "It's getting harder to tell. What's wrong with you?" He asked as he smacked his sonic.
"We're going to need a chicken leg. Who's got a chicken leg?" River asked and Teresa nudged her, pointing as Other Dave withdrew one. River took it, murmuring: "Thanks, Dave."
River walked over to where the Doctor was pointing his sonic and she threw the chicken leg into the shadows. They watched in silence as it landed on the ground, just bare bone.
River muttered as she backed away a little: "Okay. Okay, we've got a hot one. Watch your feet." She warned her team.
"They won't attack until there's enough of them." The Doctor told them tersely, as Teresa joined his side. "But they've got our scent now. They're coming."
He took Teresa's hand with him as he dashed a little over to the side, trying to keep track of the creatures in the shadows. Teresa prodded his sonic as it began acting up again, her light touch doing wonders compared to his smacking it.
"It always listens to you- this and the Tardis." The Doctor grumbled and Teresa replied lightly: "Maybe you should stop hitting them, make them like you more."
He just hummed, and she said quietly: "Trust me, Donna will be fine."
He sighed and nodded, but he remained tense. She noticed that too and she sighed.
"Doctor, you can trust River." Teresa told him quietly and he remained silent.
She didn't say any more as the woman herself joined them, asking as the sonic acted up again: "What's wrong with it?"
"There's a signal coming from somewhere, interfering with it." The Doctor muttered, sounding very unhappy to be speaking to her.
"Then use the red settings." River tried, and the Doctor looked at her strangely as he murmured: "It doesn't have a red setting."
"Well, use the dampers." River tried again and he was now staring at her openly as he told her: "It doesn't have dampers."
"It will do one day." River and Teresa muttered at the same time.
River grinned at the blonde girl, and Teresa gave a small, almost shy one in return before she wandered off back to the crew, giving them time to be alone together. She'd hoped the Doctor might trust River a little more since he was used to the idea of a woman travelling across his time stream now, but he seemed, if anything, colder and harsher.
The Doctor watched her before he took River's sonic from her and he said sharply: "So, some time in the future, I just give you my screwdriver."
"Yeah." River said bluntly, and the Doctor asked with narrowed eyes: "Why would I do that?"
River snorted: "I didn't pluck it from your cold dead hands, if that's what you're worried about."
"And I know that because...?" He challenged.
"Because Terry trusts me. And you trust her." River said firmly.
He glared at her as he hissed: "I don't trust people who think they're more important to me than my angel."
River stayed calm as she asked: "Did she tell you that?"
"Did you make her feel that way?" The Doctor countered and River replied lightly, though she was frowning a little: "You've seen her almost as much as I have. You know what she's like in her younger days. How many times did you have to deal with her going on about Rose?"
The Doctor frowned as he asked: "So, she thinks of you as she did Rose?"
"God no; it's far more complicated." River scoffed. He opened his mouth and she raised a hand, murmuring: "Spoilers."
His mouth snapped shut audibly and River noticed. She scolded: "Doctor, there are six people in this room still alive. Focus on that."
He rolled his eyes and River muttered: "Dear God, you're hard work, young."
"Young?" He repeated indignantly and then he snarled loudly: "Who are you?"
"Oh, for God's sake!" Teresa snapped as she marched back over. "River, please, just tell him before we all die."
River looked at her in surprise, asking incredulously: "Are you sure?"
"Dead certain, he won't believe you otherwise." Teresa muttered, scowling right back at the Doctor as he scowled at her before she stormed away again. River hesitated as the Doctor turned murderous eyes on her.
His expression told her he was ready to kill for her causing Teresa to be angry with him, but she knew exactly what would pacify him. So with a sigh, River leaned in and whispered into his ear.
Teresa watched from afar, arms folded, and watched as the Doctor's face changed into one of absolute shock and a tiny bit of wonder.
"Are we good?" River asked quietly and he just stared at her dumbly. River repeated: "Doctor, are we good?"
He finally snapped out of it and replied shakily: "Yeah, we're good."
"Good." River murmured softly, and Teresa muttered: "Finally."
He glanced at her, wondering what was going through her head. She had no idea, not yet, so what did she think River told him? Her foreknowledge might've hinted at one part of the secret- his secret- but had she thought that would be enough to make him trust this strange woman?
And that wasn't event the beginning. How could River know that about Terry, something very few people had been trusted with? Who was River Song? What did she mean to him, and what did she mean to his Terry? But as River took her screwdriver back and walked away, he shook himself and refocused on the present situation. There would be time to think later.
And an idea popped into his head.
"Know what's interesting about my screwdriver?" He asked to the group at large as he walked back to join them. "Very hard to interfere with. Practically nothing's strong enough. Well, some hairdryers, but I'm working on that. So there is a very strong signal coming from somewhere, and it wasn't there before. So what's new? What's changed?"
When no-one responded, he shouted impatiently: "Come on! What's new? What's different? And no, angel, you can't speak."
Teresa rolled her eyes, wondering why he'd point out the obvious. River rolled her eyes, knowing he was just reaffirming his claim on the blonde girl.
Other Dave muttered: "I don't know. Nothing. It's getting dark?"
"It's a screwdriver. It works in the dark." The Doctor said flatly, but then he looked up and murmured thoughtfully: "Moon rise. Tell me about the moon. What's there?"
Lux answered: "It's not real. It was built as part of the Library. It's just a Doctor Moon."
"What's a Doctor Moon?" The Doctor asked, and Lux explained: "A virus checker. It supports and maintains the main computer at the core of the planet."
The Doctor switched on his sonic and murmured: "Well, still active. It's signaling. Look. Someone somewhere in this library is alive and communicating with the moon. Or, possibly alive and drying their hair."
He made the signal stronger and muttered: "No, the signal is definitely coming from the moon. I'm blocking it, but it's trying to break through."
His sonic flashed and River gasped: "Doctor!" and the same time Teresa jumped up and gasped: "Donna!"
The sonic was flashing a holographic image of Donna, and the Doctor called: "Donna!"
The image disappeared and Teresa hurried over as River said frantically: "That was her. That was your friend! Can you get her back? What was that?"
"Hold on, hold on, hold on. I'm trying to find the wavelength. Argh, I'm being blocked." He groaned, when Anita called in a small voice: "Professor?"
Teresa froze, turning to the woman even as River said distractedly: "Just a moment."
"It's important." Anita said in a shaky voice as a tear dripped down her cheek and Teresa said quietly: "She has two shadows."
Everyone spun around immediately and River said quickly: "Okay. Helmets on, everyone. Anita, I'll get yours."
The Doctor pulled Teresa into his arms as Anita murmured: "It didn't do Proper Dave any good."
"Just keep it together, okay?" River suggested and Anita said calmly: "Keeping it together. I'm only crying. I'm about to die. It's not an overreaction."
Teresa tugged on the Doctor, pulling him with her as River placed the helmet on Anita's head. The Doctor murmured: "Hang on."
He soniced her helmet visor, making it completely black and River gasped: "Oh God, they've got inside."
"No, no, no." The Doctor corrected quickly. "I just tinted her visor. Maybe they'll think they're already in there, leave her alone."
Teresa was twisting her hands nervously while River asked: "Do you think they can be fooled like that?"
"Maybe." The Doctor muttered. "I don't know. It's a swarm. It's not like we chat."
He pointed out, and Other Dave called: "Can you still see in there?"
"Just about." Anita replied tightly.
Other Dave was about to come closer and the Doctor said quickly: "Just, just, just stay back. Professor," he said with forced calm as he gave Teresa a look, "a quick word, please."
"What?" River asked, as Teresa nodded at the Doctor. He nodded back as he knelt down and said to River: "Down here."
She joined him, and he muttered: "Look, you said there are six people still alive in this room."
"Yeah, so?" River asked in confusion and he asked quietly: "So, why are there seven?"
She rose slowly and they all turned to Zombie Dave who called: "Hey, who turned out the lights?"
"Run!" The Doctor shouted as he grabbed Teresa's hand and they all ran as Zombie Dave called: "Hey, who turned out the lights?"
They sprinted out and through a high level walkway into a different skyscraper building when the Doctor paused and pushed Teresa into River.
"Professor, go ahead." He ordered. "Find a safe spot. Take Terry."
"What?" Teresa cried indignantly while River protested: "It's a carnivorous swarm in a suit. You can't reason with it."
"Five minutes." The Doctor told her, and she turned to go but Teresa protested, crying: "No!"
"Terry!" He turned to grasp her shoulders and looked her right in the eye as he promised: "Five minutes."
"You lie." She pointed out and he replied: "Sorry, angel. But give me five minutes."
River tugged her along and Teresa followed, glancing back desperately while River called: "Other Dave, stay with him. Pull him out when he's too stupid to live. Two minutes, Doctor."
She warned, and Teresa shouted: "Other Dave, be careful!"
"Oh, I hate the sound of that." River moaned as they ran.
"What?" Teresa asked and River elaborated: "You only ever make it a point to tell people to be careful when something bad will happen to them."
Teresa hesitated, but River dragged her on as she said impatiently: "No, come on, if something happened to you the Doctor would kill me."
"Why? You're his future." Teresa pointed out and River sighed and muttered something that sounded like: "Whatever."
------------------------------------------------------------------------------------------------
Night had fallen as Teresa waited with River in the round room they'd chosen to stake out in. River was checking the shadows with her sonic, although she kept glancing at the blonde girl beside her. She was looking continually more anxious and River attributed it to the Doctor's continual absence.
Wanting to try make her feel better, River said lightly: "You know, it's strange how different this Doctor is."
Teresa glanced over in surprise, before she thought about it.
"I suppose..." She murmured and River continued, trying to prompt the girl: "I mean, I'm so used to him swaggering about in his ridiculous outfit. This man's more... angry."
Teresa chuckled as she replied lightly: "I think that's just because he doesn't know you yet. You should've seen Nine's temper with me the first time I met him. And that wasn't even his first time seeing me apparently."
"Oh, you told me that story." River mused and Teresa smiled.
"It was funny watching the Doctor sit through the story, looking so anxious." River added and Teresa laughed again.
"I look forward to that..." She trailed off as she thought about the outcome of this night. If she went through with it, that memory would never have existed. But, in its place, new memories might come to life for River, memories with the Doctor.
She was broken from her thoughts as River mused: "Hm, it was a good day. Although I'll never forget his arrogant back as he walked off with you to the Tardis, opening the doors with a snap of his fingers, just to provoke me and make you smile."
Teresa frowned. Wait, what? But she forgot about it as the Doctor called from the second floor: "Spoilers."
Her eyes lit up and River almost chuckled as the Doctor walked quickly into the room, heading straight for the blonde girl as she stood up to meet him.
"And nobody can open the Tardis by snapping their fingers." The Doctor added to River although his eyes were on Teresa, sweeping her quickly as he walked, checking that she was unharmed. River shrugged but she did roll her eyes when he glanced at her briefly to give her a begrudging nod of thanks for keeping his angel safe, before he hugged the girl close.
"Are you alright?" Teresa asked him as he let go and he replied easily: "Course I am."
"No, I meant you're alone. Are you okay?" She told him quietly and his eyes softened.
"I will be." He promised quietly as River also noticed Other Dave's absence.
She didn't comment on it as the Doctor then turned to Anita and asked: "How are you doing?"
"Where's Other Dave?" She asked and the Doctor answered quietly: "Not coming. Sorry."
She asked shakily: "Well, if they've taken him, why haven't they gotten me yet?"
"I don't know." The Doctor murmured as he examined her two shadows. "Maybe tinting your visor's making a difference."
"It's making a difference all right." Anita muttered bitterly. "No one's ever going to see my face again."
"Can I get you anything?" The Doctor asked seriously, and Anita replied lightly: "An old age would be nice. Anything you can do?"
"I'm all over it." He promised, and he turned to go, taking Teresa with him when Anita called: "Doctor."
He turned back expectantly and she told him: "When we first met you, you didn't trust Professor Song. And then she whispered a word in your ear, and you did. My life so far. I could do with a word like that. What did she say?"
He just gazed at her and she chuckled a little as she said with a forced cheerful tone: "Give a dead girl a break. Your secrets are safe with me."
Teresa smiled at the brave girl, and waited, watching for the penny to drop.
"Safe." The Doctor murmured and Anita asked confused: "What?"
But the Doctor had figured it out and he muttered: "Safe. You don't say 'saved'. Nobody says 'saved'. You say 'safe'." He whirled on Lux and called: "The data fragment! What did it say?"
The startled man replied: "Four thousand and twenty two people saved. No survivors."
"Doctor?" River asked questioningly, but he wasn't listening as he paced, muttering: "Nobody says 'saved'. Nutters say 'saved'. You say 'safe'. You see, it didn't mean 'safe'."
He turned to Teresa as he realized: "It meant, it literally meant, 'saved'!"
She smiled softly and nodded, and the Doctor reached in to pull her in for a tight hug.
"Right, then. Now we know." He said determinedly as he dragged her with him to the terminal and River followed.
He looked through the Archives and explained to River: "See, there it is, right there. A hundred years ago, massive power surge. All the teleports going at once. Soon as the Vashta Nerada hit their hatching cycle, they attack. Someone hits the alarm. The computer tries to teleport everyone out."
"It tried to teleport four thousand twenty two people?" River asked in disbelief and the Doctor shrugged as he commented: "It succeeded. Pulled them all out, but then what? Nowhere to send them. Nowhere safe in the whole library. Vashta Nerada growing in every shadow. Four thousand and twenty two people all beamed up and nowhere to go. They're stuck in the system, waiting to be sent, like emails. So what's a computer to do? What does a computer always do?"
"It saved them." River realized as she smiled at the Doctor and Teresa. He nodded as Teresa smiled back at River, before the Doctor dashed to a large polished table and began to draw on it.
"Oh, that was a beautiful table, too." Teresa sighed and he glanced at her.
"Sorry?" He tried and she shook her head.
"Continue." She gestured at his drawing and he quickly explained as he drew: "The library. A whole world of books, and right at the core, the biggest hard drive in history. The index to everything ever written, backup copies of every single book. The computer saved four thousand and twenty two people the only way a computer can. It saved them to the hard drive."
Suddenly an alarm began ringing and Lux asked in alarm: "What is it? What's wrong?"
They ran to check the terminal, but the computer called aloud: "Autodestruct enabled in twenty minutes."
"Oh, no." Teresa breathed. She knew and now, she had a decision to make. Except, there wasn't one. She had made her choice long before this. Now, she just had to see it through.