Far beneath the ship
The world is mourning
They don't realize
He's alive

No one understands
But Major Tom sees,
"Now the light commands
This is my home,
I'm coming home."

Earth below us
Drifting, falling
Floating, weightless
Coming home...

- Major Tom (Coming Home), Peter Schilling

Booth's fingers rested idly on the wheel as they rolled down the empty county road, stretched out before them like a long, winding asphalt river. It had already been past dark by the time they were done investigating a suspect's home just over the Maryland/West Virginia state line, but rather than fork over the money for a hotel room, Booth decided he could make the three and a half hour drive that night. It wasn't that long, he insisted, and he wasn't tired.

Actually, he was tired, very much so. Ever since Brennan had made the heart-wrenching reveal in Sweets's office of having been locked in a car trunk for two days as a young girl, he had not found much refuge in sleep. Every time he dozed off, he dreamed she was locked in a trunk again, running out of oxygen, and he couldn't force it open no matter how much he pushed, pulled, or shot at the handle. Just as when she had been taken by the Gravedigger, he was powerless, and she was running out of time. Running out of air.

He woke from each of these dreams with the breath stolen from his chest, clammy and shaken, overwhelmed by the urge to call and make sure she was alright. She would surely be asleep, though, and he wasn't going to bother her with his silly nightmares. He felt like a child again, afraid to sleep without the spaceship nightlight twinkling in the corner of the room.

He looked over at her, watching her stare into the lines of her hands as if they were a map of the universe, or a collection of constellations, held tightly in her palm. There was so much of her, he realized, that he did not know. For as much as he knew of her past, it was probably only a small portion of what she held within her. She was as unknowable as the solar system; every time he felt like he was getting a handle on who she was and where she had been, some new and uncharted territory presented itself that forced him to reevaluate everything he thought he already knew. He turned back to the road, an expanse of blackness broken by the high beams of his SUV, and wondered how much of her he would ever understand.

Brennan looked over at Booth's fatigued features and withheld a sigh. She knew he was lying when he said he wasn't tired—he looked exhausted. She could commiserate with the feeling; for the past week she had averaged maybe three hours of sleep a night. Every time she came close to slipping into unconsciousness, his low, rushed words echoed around her head—I probably would have killed myself. When she tucked the handkerchief into his breast pocket she let her hand linger on his chest, feeling the gentle thud of his heart beneath her fingers. Feeling his life, his aliveness, what survived so many years of tragedy. Just to remind herself that yes, he was alive and present, as was she.

It wasn't the first time she had been forced to imagine her life without him, far from it. When he had "died" the previous year, she'd had no choice but to confront such an extraordinarily dismal future. Those had been sleepless weeks as well. And again, several months prior when the Gravedigger had taken him and nearly blew him up, she had been forced to consider the possibility of losing him. The nights after that, though, as she lay awake in the dark, she need only think of the feeling of pulling him into the helicopter, of having her arms around him and feeling that he was there and safe, and sleep would come.

But something about hearing the words come from his own lips—that he could have ended his own life, that he could have stolen from her, without ever knowing, the one thing that made her feel whole—somehow shook her in a way their previous experience hadn't. In times before, she had only been made face the thought of losing him from that point forward in her life. Now she found herself, late at night and in the quiet moments at work when she stared down into the emptiness of a human skull, tangled up in the idea of having never had him at all.

She thought about all the late night meals at the diner, sharing a box of Pad Thai or singing old Poco hits over milkshakes. She thought about the heart to hearts and the gifts they gave one another, little understated tokens of their affection for one another. She thought about his quirky, self-deprecating comments, as a means of both boosting her ego and deceiving others into thinking he was less intelligent than he was. She thought about guns and guy hugs, and bad backs and teeth and manuscripts and pigs. Mostly she thought about his large, warm shoulder leaned against hers, his face turned down slightly towards hers, smiling kindly. To live without that, to have ever lived without that, was more now than she could imagine, and it hurt her just to think about how near that reality had been.

There was so much beyond what she knew about her partner, and she was painfully aware of that. His life had rewarded stealth and secrecy, and punished emotional openness. It was a typical response of anyone exposed to an abusive situation: the fewer emotions exposed to the open, the fewer opportunities for their abuser to use those emotions against them. The less people know about you, the less they can hurt you. It was a defense mechanism she herself had employed successfully in many instances throughout her life, and even did still. The unfortunate side effect was that by living a life of emotional secrecy, you also bar those who care for you from seeing the vulnerable side of you, and thus ever really knowing you. Even after four years, she felt that she only really understood one side of Booth, one aspect of who he was. The other part was so well hidden that she could make very few guesses as to what the darkness held. She could not decide how much that bothered her, or rather, how much it should bother her.

"It's a nice night," he said, breaking the silence and interrupting her thoughts. She looked up from her lap, first at him and then leaning forward slightly to look up at the clear sky overhead. Since the road was largely unlit, stars were scattered across the black emptiness by the thousands, shimmering like light cutting through a dense fog. The moon was bright and full, a perfect orb hanging in the sky, seeming to follow them for miles.

"It is," she agreed, leaning back into her seat.

"You sometimes forget how many stars there are out there, being in the city so much," he commented.

"The city lights certainly do make star-gazing difficult." She didn't mean to sound clipped, she was just so engrossed in the mire of her own thoughts that she was having a hard time returning to the present. She stared at the side of his face, tracing his profile with her eyes—his heavy brow ridge, the bump on his nose, around his lips and down around the soft turn of his chin and the line of his strong jaw.

"Have you ever noticed that the moon always looks the same?" he asked out of nowhere, causing her to pause for a moment before answering.

"That's because you always see the same side of it," she said.

"Yeah?" Booth asked. She nodded. "So there is a dark side of the moon, huh?"

"No," she said. "Not a dark side."

"Try telling that to Pink Floyd," Booth joked. She smiled.

"It's not a dark side, Booth, just a far side. All parts of the moon see light at some point during its phases, but one side of the moon always faces away from us, while one is always faced towards us."

"But doesn't the moon turn just like the earth does?" he asked, and she found herself impressed by what he did know about their planets orbiting celestial bodies. It was admittedly more than most people knew, which was either commendable on his part or a sad statement on society's general level of education. She suspected it was a little of both.

"It does," she said, "but because the moon's rotation around the earth matches the earth's revolution around the sun, the near side of the moon is only ever visible."

"So the earth doesn't ever get to see the moon's dark side, then," Booth said carefully after a moment of thought. "The moon is careful to always show it the same face."

"Far side," she corrected. "Not dark side. But yes, that is correct. From earth we will never see the far side of the moon because it never faces us." He seemed to ponder that point for a moment, then huffed.

"That must be hard work for the moon, to always be making sure the right side faces the earth," he said pointedly, watching Brennan out of the corner of his eye as he spoke. She furrowed her brows.

"No," she said hesitantly. "Gravity does all of the 'work', the moon puts forth no effort whatsoever. It can't, it's a moon." Booth sighed.

"I mean," he said emphatically, "maybe the moon is afraid to show its dark side—"

"Far side," she corrected.

"Far side, whatever. Maybe the moon is afraid to show its far side to the earth, because nobody on earth has ever seen it, and it's a scary place."

"The far side of the moon isn't scary," Brennan argued. "NASA has taken many pictures of the moon's far side. It's pocked with craters, much less smooth than the near side, but aside from that there isn't much of a difference."

"But maybe the moon is afraid the earth would see that difference, and think something was wrong with it," he insisted, slightly peeved with her slowness. "Maybe the moon is scared that if earth saw how messed up the far side of the moon was, earth wouldn't want anything to do with the moon anymore and would just send it flying out into space all alone."

"That makes no sense," Brennan said plainly. "The earth cannot make a conscious decision to withdraw its gravitational… oh," she said, lips forming a small ring, comprehension finally dawning. "This is duck hunting, isn't it?" He nodded and she bit her bottom lip as she scrambled mentally for the things she wanted to say, the ways she wanted to say them.

"Well," she said, wetting her bottom lip with her tongue like she often did when she calculated her words. "Temporarily suspending the laws of physics… yes, perhaps the moon is unwilling to let the earth see its far side. After all, the moon has spent millions of years keeping its far side hidden—it must be very uncomfortable with the idea of revealing that to anybody, even the earth."

"The moon shouldn't be scared to let earth see its far side," Booth said. "Maybe the earth wants to see the moon's far side, so it can really know the moon, all of it."

"Well, if we're dismissing the laws of physics, then maybe the earth has been only showing the moon one of its sides also. Maybe the moon has never seen the Pacific Ocean before, because the earth always faces the moon in such a way that the Pacific Ocean is not visible."

"What does the moon want to see the Pacific Ocean for?" he asked, caught off guard at having his metaphor turned on him. "There's nothing great about the Pacific, nothing the moon needs to see."

"Perhaps for the same reason the earth wants to see the far side of the moon. To, how did you say it? Really know it. You can't possibly presume to truly know the earth until you've seen all of its oceans, Pacific included." He drummed on the steering wheel, staring out at the road ahead of him with a look of deep concentration. When she decided to play the metaphor game, she was really good at it.

"Maybe you're right," he said. "Maybe the earth has been a little secretive. But that's how the earth protects itself from, uhm… aliens. If the aliens can't see the Pacific Ocean and see how terrible it is, they'll think the earth is strong."

"I think the moon would be very understanding of the earth's fear of aliens," Brennan said hesitantly. "The moon understands aliens very well."

"I know it does," he said quietly. "I mean, the earth knows."

"If the earth knows," she said, "then the earth logically ought to know that the moon wouldn't judge the earth's fear of aliens, because the moon has dealt with so many of its own encounters of the third kind."

"Yeah," he sighed. "You're right. The earth knows that, too. The earth just has a hard time letting other planets, even the planets it's closest to, see the Pacific."

"The moon isn't a planet, Booth, it's a moon," she said, seeming to forget their suspension of reality. He laughed.

"I bet you think Pluto's not a planet either," he said. "Besides, the moon is like, ten times better than all the other planets. If it's not a planet, that's only because it's too good to be a planet."

"Well," she said, concealing her smile, "the moon thinks pretty highly of the earth as well. After all, without the earth's gravitational pull, the moon would have no orbit, no purpose. The earth makes the moon what it is. If the earth ever let it go…" At this point Booth pulled the car to the side of the otherwise-empty road, parking it and turning to face his partner completely.

"There's no way the earth would ever let go of the moon," Booth said in a serious tone. "Near side, far side, dark side, doesn't matter. There is nothing—nothing—on the far side of the moon that could ever make the earth let go." Her eyes flicked back and forth between his, which were intense and heavy with resolve. She pressed her lips together briefly.

"If the earth is in it for the long haul," she said carefully, "then the moon is more than prepared for whatever the earth might be hiding." He reached his hand across the space between them, resting it on her arm.

"Like I said, I'm not going anywhere. You can't scare me off. And if the Pacific is what you really want…"

"I deal with dead bodies every day, Booth. Do you really think a few skeletons in your closet will frighten me?" she asked, wry smile touching her lips. "When you're ready to… to see the far side, to let me see the far side, I'll be here." She reached her other hand over and placed it on top of his, squeezing it gently. He smiled down at it.

"I'm ready when you are," he said.

"I think I am," she said, voice wavering but somehow certain. He looked down at her hand atop his, and reached his thumb up over top of it so he could rub it along the back of her hand.

"All systems go, then?" Booth asked, disarming smile spreading across his face. She looked out the window briefly, the moon's bright eye seeming to watch them on the side of the road. She looked back at him, nodding.

"All systems go."