River strolled around the console, running her hand over it and inspecting each part with careful scrutiny. The Doctor watched with amusement. He could tell by the way she was studying it that she hadn't had a chance in her timeline to really do so yet. This must be it, he realized, the moment he would teach her about the TARDIS. She paused by a blue button and traced a finger around it.

"That's the—" the Doctor began.

"Stabilizer," River interrupted.

The Doctor looked surprised. "Er, what? How do you know that?"

Shrugging, River glanced at him and said, "I just know." There was still the vaguest flicker of youthful innocence in her eyes nearly hidden behind layers of pain and suffering. Her gaze returned to scan the console. "I know what they all do."

"So you think you know everything about the TARDIS, do you?"

"I know quite a lot, yes," River replied.

"Come with me. I want to show you something." The Doctor started down the steps toward the door when he looked back and saw her reaching for the scanner. "Ah-ah, no cheating."

"But we need to—"

"No we don't, just come see."

Shooting one last glance at the monitor, River followed him. When he reached the door, he leaned comfortably against it and waited for her to join him.

"So," River said, "what are we looking at?"

The Doctor slid his hand behind his back and opened the door, never taking his eyes off River's face. An incredible expanse of stars of varying colors and intensities stretched across the open doorway like some fantastic mural. The barest hint of a nebula was barely visible at the corner, its clouds curling seductively just within River's line of sight. She strained to see more, standing on her tiptoes to peer around the Doctor, who was still standing stubbornly on the threshold.

"Move," River said with a hint of impatience in her voice, "I want a better look."

"As you wish," he said. The Doctor let his body go limp and fell backwards out the door. River gasped as she grabbed for him, but he suddenly stopped falling. He righted himself to what would be a standing position and hovered there, held suspended in space by some unseen force.

"How? I— What sort of… of… lunatic just falls backwards out of a spaceship in deep space like that?" River demanded.

The Doctor laughed, "You'd be surprised."

"You're mad," River said, still trying to catch her breath from the shock. "Really, just… completely bonkers."

"Yes, and always remember that."

"I hate you," she said with a slight shake of her head.

"No, you don't," the Doctor said, smiling. He held out his hand toward River, but she hesitated.

"What is it?" she asked.

"It's an air corridor. Perfectly safe, loads of fun. Great for parties and rescues and escapes," he said as he motioned with his hand to encourage her to join him. "Come on, don't you trust me?"

"I don't know," she replied slowly.

The Doctor dropped his hand and studied her eyes. The complete and implicit trust that he was so used to seeing wasn't there. His hearts ached and his chest tightened as he realized what he must've done to her all those times he didn't trust her.

"All right, if you don't trust me, trust her," he said, nodding toward the TARDIS. "She'd never let anything happen to you."

River considered for a moment then nodded and took his hand as he offered it again. She took a deep breath and stepped off the edge. Wobbling, she reflexively grabbed the Doctor's arm with her other hand as she tried to get used to the feeling of weightlessness. After a few moments of steadying herself, she released his arm leaving only their hands linked.

"How do we get back?" she asked.

"Simple," he said, letting go of her hand. "Think of the TARDIS."

River glanced back toward the blue box and felt herself pulled gently toward it.

"Now, think of me," he said with his hand still outstretched toward her.

"This is brilliant," she laughed as she felt herself pushed back to him. "What happens if I think of one of those stars?"

"Try it."

Scanning the sky, River picked a star and focused on it. She started moving slowly but as she got the hang of it she picked up speed. Soon she was joyfully spinning through the corridor. The Doctor watched her for a while, admiring the beauty of her slender form twisting and turning through space as comfortably as a fish through water. He smiled to himself as he set off after her.

"It's wonderful! It's like flying!" River laughed as he caught up to her. "Is there an end to the corridor?"

"Probably. But don't worry, the old girl won't let us go too far."

"Right then, let's go." River grabbed the Doctor's hands and took off with all the speed and force she could manage. When he finally was able to gain his balance and keep pace with her, she gave him a smile with a mischievous twinkle in her eye. River twisted at her waist and started them spinning together, leading him in a dance through the air corridor. The Doctor laughed and turned with her as they danced together until they were so far from the TARDIS, its light blended in with the curtain of stars behind it.

River placed a hand on his shoulder and slowed them both. She rested her head against his chest and placed her hands over each of his hearts, smiling to herself as she felt their rhythm increase. The Doctor wrapped his arms around her and hugged her tightly, then continued to hold her close. They floated quietly together, surrounded by the infinity of time and space. River shifted slightly so her ear was over one of his hearts as she traced Gallifreyan symbols over the other.

"I suppose you just know those too," said the Doctor as he watched her.

"Yes, always have. I don't know how, it's just something normal for me."

The Doctor thought about it, then he realized. "Oh! The TARDIS! You must've learned it from the TARDIS!"

"When have I been in the TARDIS that I could've learned it?" she asked, looking up at him questioningly. "How old was I?"

"Er… ah… I'd say probably about… maybe around… zero."

"What? How could I be zero? I wasn't born on the TARDIS, was I?"

"No. Well, sort of. But not born born. More like started born, in a way. You were kind of on it again after you were born, though, but not really."

"Again? How could I be on it again if I wasn't bo… oh…" A knowing grin spread across her lips. "You mean my parents had sex in the TARDIS and that's when I was conceived."

"River!" The Doctor blushed and pushed away from her. "You don't have to be so… so blunt about it! I was trying to be delicate!"

"What?" River asked as her smirk transformed into an innocent smile. "That's what happened isn't it?"

"Well, yes, I mean… but still!" He straightened his tie and nervously tugged on his lapels. "Anyway," he coughed, trying to calm himself and change the subject, "that affected you. Apparently more than I realized. The TARDIS must have imprinted some of her knowledge on you."

"So then I learned from the best?"

"I suppose you could say that."

As she watched the pink fade from his cheeks, she asked, "Are you always this adorable when you're embarrassed?"

"What? No!" he exclaimed, some of the color returning to his cheeks. "In fact, you hate making me blush. You… you never, ever do it because you hate it so much!"

"Oh, I somehow doubt that," she said.

Silence fell between them. River thought about holding his hand and found herself drawn to him. She slipped her hand in his and squeezed. He tilted his head toward her and smiled.

River studied his face. He looked calm again, exactly what she was waiting for. "Have we had sex in the TARDIS?"

"What?" He pushed away from her again, his arms flailing and the flush returning to his cheeks. "River! I don't—what? That's hardly appropriate!"

"Come now," she said, moving closer to him again. "You've obviously met me when I'm older, and I can tell you love me. Or at least the future me."

"No, but maybe, but spoilers! Spoilers, spoilers, spoilers! Shut up!"

"That 'spoilers' thing really is a bit annoying," she commented.

"Oh, you have no idea," the Doctor said as he raised a hand to his forehead and rubbed his temples.

"But that's okay." River said with a smirk. "I got my answer."

He blinked at her, "What answer? What? No you didn't!"

"Yes I did," she said with a slight giggle. "You are always that adorable when you're embarrassed."

"Okay! Yes! Right! Time to head back now, I think!" He turned away from River's gaze and started moving toward the TARDIS. Moments later, River passed him, flying backwards toward the blue box with a flirty smile. By the time he set foot in the artificial gravity of the TARDIS, River was standing at the foot of the stairs to the console platform, gazing up at it.

"It isn't an air corridor, by the way." River said. "She says it's a gravitronic excursion oxygen extension."

"What? Who says that?"

River motioned toward the console.

"The TARDIS? MY TARDIS? You think you can talk to my TARDIS?"

"No," River said simply as she turned toward him. "I know I can."

"Well, it's an air corridor!" He exclaimed as he strode past River up to the console, "It's always been an air corridor, and it always will be an AIR CORRIDOR!"

River walked over and stood next to the Doctor. She glanced up at the central column rising from the console and said, "She thinks you're bad with names. Except for hers, she likes it. What's her name?"

"Why don't you just ask her since you're such brilliant friends now?" he asked grumpily.

"She said to ask you. She says it embarrasses you for some reason, so she'd let you tell me if you want."

"It's, um. S—Sweetie," he lied.

"Sweetie?" River asked skeptically.

"Yes. Sweetie."

"You're lying."

"Might be. Might not be," he said in what he hoped was a casual voice.

"Well, I kind of like it. Even if you are lying," River said. She paused then suddenly grabbed him by his lapel and pulled him into a kiss. It only caught him off guard for a moment as he flailed before he regained control of his limbs and embraced her, his fingers finding their way to mingle with the ends of her curls. As they parted, she reached up and ran a finger down his cheek. He smiled in return.

River turned back toward the console and said, "The air corridor was fun, but let's go somewhere a little more exciting now." She glanced at the Doctor and winked, "You and me, sweetie."

A little wobbly, the Doctor stepped back and leaned against the railing. He watched River start the TARDIS transport sequence. She was doing it all wrong, of course, or at least not how HE did it. But right then he didn't care. Watching River fly the TARDIS was the most beautiful thing in the world, and he trusted her to take him anywhere.