A Hobbit would have called it luck.
Hobbits believed rather firmly in the power of good luck and proscribed that a favor given would be a favor soon returned. Sharing a day's baking could mean a lovely birthday gift when the time arrived and offering a fine spread of tea to a neighbor might bring a happy find of mushrooms on a fellow's next walking holiday.
Dwarves, Bilbo had found, scoffed at the very idea of luck. A Dwarf followed their own path and made their own way, with Mahal's wisdom to guide them. Luck, poor or otherwise, had little to do with it as far as they were concerned.
Living in Erebor had not swayed Bilbo overly much from a Hobbits way of thinking. The proper amount of meals in a day was not less than five, boots were an inconvenience not to be borne and a little earned luck could settle on one's shoulders like a dusting of snow, waiting to fall where it was needed.
Today his luck hinged on a single forgotten book and any other day, Bilbo would have gotten by without it rather than make his winding path back to the King's quarters to find it. The mountain was a confounding maze of stairways and pathways and hallways and sideways, and Bilbo preferred not to tempt his sense of direction more than was necessary. How it was that Thorin could lose himself on the simple paths of Hobbiton and yet manage this labyrinth, Bilbo couldn't begin to guess.
Yes, any other day he would have left it but today he and Ori were working on a translation together, a meeting that had been planned weeks before for neither of them had so many moments to spare at any given time. Any other day wouldn't have seen Bilbo back in their rooms until after supper, so it simply had to be luck that sent him back this day to find Thorin collapsed on their floor, his face a rictus mask of pain with both hands clenched around his knee.
Luck, it simply had to be luck because the only other option was that this happened often and that was a thought Bilbo simply could not stand.
"Thorin!" Bilbo gasped aloud, books and papers falling in an untidy scatter at his feet. Bilbo paid them no mind, scrambling to his own knees next to Thorin. Only to yelp as Thorin pushed him away, a hard enough shove to send him stumbling back.
"Go away!" Thorin snarled, an order Bilbo ignored, considering how utterly ridiculous it was. Yes, of course he'd go away and simply leave Thorin to the floor, that was certainly reasonable. Perhaps he could cover him with a doily and turn him into a somewhat lumpy, hairy end table.
Pain was surely making Thorin's normally clever fingers clumsy and Bilbo shoved them aside impatiently, yanking up his trouser leg to reveal the cunning brace surrounding his knee beneath it. Under his somewhat trembly fingers, the brace fell away easily, giving him access to the ruined, bunched muscles and without thinking, Bilbo dug his thumbs into them mercilessly.
A clotted hiss of pain seethed through Thorin's gritted teeth, a single word couched in it, "Don't—"
"Don't what, help you?" Bilbo scoffed aloud, swallowed down the fear that had threatened to choke him. It hardly showed a bit in his voice, only the faintest tremor as he added scathingly, "I supposed you'd prefer I simply left you here to commune with the floor, is that it? Dreadfully sorry to be interrupting the conversation!"
"Balin or Dwalin would have come looking for me soon enough!"
"Indeed?" Bilbo said and there was the hoarseness, mingled with hurt. "You'd trust Balin or Dwalin to see you like this, but not me?" For a long moment, Thorin offered no reply, only shifted restlessly, pushing up on his good knee until he could rise to his feet. Bilbo watched him doubtfully, hands outstretched to help him catch his balance but Thorin only staggered to a nearby chair, collapsing in it and panting for breath as he stretched out his damaged leg. He said nothing when Bilbo knelt beside him again, dropping to the floor with an ease that Thorin could no longer manage and it was only when Bilbo laid his hands again on the mangled scars of his knee that Thorin finally spoke.
"It is not about trust," Thorin gritted out. His lips were still pale, hard lines of pain creasing his face. Beneath his hands, Bilbo could feel the ruined muscles spasm relentlessly. It took a fair amount of effort from both of them to straighten his leg, working it back and forth as much as the taut muscle allowed.
"Then what?" Bilbo muttered irritably. He dared a glance upward and found Thorin was not looking at him. His head was dropped back on the chair and his eyes focused at the ceiling, as though answers to Bilbo's questions might be found chiseled into it. Cold sweat was dampening his face but at least there was some color to his face. "Why, precisely, are others allowed to help you but not me?"
"I don't want your help!" Thorin growled out, trailing into a near yelp as Bilbo gave a forceful tug, straightening his damaged knee. Instantly, Bilbo eased his grip, muttering a low apology.
"All right, so I'm not a particularly good helper," Bilbo mumbled. "But at least I'm here! Were you planning on lying on the floor until Balin returned tonight? Or were you hoping that somehow I'd mistake you for a piece of furniture? Did you think I'd hang my coat on your ear and hie off to bed with nary a glance?"
"I was...I did not want you to see--" Thorin hissed out a long breath as Bilbo dug his thumbs again into the ruined muscle, pressing forcefully, and finally he felt the spasms ease. Thorin collapsed back into the chair, trembling, his shirt clinging sweatily to him.
Bilbo kept up the massage, gently, fingers tracing rough scars and twisted flesh. "You didn't want me to see this?" he prompted softly. "Thorin, I've seen you a great deal more naked than this. I know what scars you have."
"You do," Thorin said and there was a wealth of weariness to his tone, coupled with the belligerence that Bilbo knew so well. Honestly, without it, he might well not recognize Thorin. "I have no fear of you seeing old wounds."
"No? My backside would beg to differ, considering you nearly shoved me into a wall when I tried to help you up."
"If you would have left when I told you--!"
"Well, I didn't, I'm still here, so what exactly is it that I'm not supposed to see, if I may ask," Bilbo snapped, his own temper flaring. "You say you trust me, you agree I've seen you bare-arsed and bandaged, so perhaps you'd care to explain precisely what is the problem here?"
"I will not have you see me as weak!" Thorin shouted, echoing through the chamber. The moment the words left him, seemingly torn from him, Thorin shut his mouth so hard Bilbo heard his teeth click. Again, he took refuge in the ceiling, hands clenched in his lap and the only part of him that did not near vibrate with tension was his wounded leg, the muscles still warm and relaxed beneath Bilbo's still hands.
"Weak?" Bilbo blinked, mouth working. "Weak," he repeated, tasting the word, rolling it over his tongue like a bitter wine. "Thorin, I've used many words to describe you, not a few of them ones that I shan't be repeating in front of my nephew, but weak has never been one of them."
Thorin's nostrils flared as he took a sharp breath, though his eyes did not shift and he said nothing. With a quiet sigh, Bilbo rested his cheek against Thorin's mangled and badly-healed knee, pressing a soft kiss to the wide bands of scar tissue.
"You listen to me, Thorin Oakenshield," Bilbo whispered, fiercely. "You are quite correct; I've seen your old wounds and all your scars, that's true. What you seem to have forgotten is I've also seen exactly how those scars came to be. I saw you leading your people on a quest no one thought could succeed. I've seen you fight battles that many did not survive, and I even," Bilbo's voice caught, and he pushed past it steadily, "I've even seen you throw off the madness that haunted both your father and your grandfather, so I'll thank you not to tell me what I see when I look at you! I've seen plenty, I can draw my own conclusions."
"Weak," Bilbo repeated, attempting to scoff at the pitiful word and succeeding more at choking on it. "Honestly!"
The silence held, only broken by their breathing, Bilbo's a touch clotted and he wished rather fiercely that he dared to fish his handkerchief out and give his nose a good blowing. Perhaps neither of them wanted to give away a weakness or two, Bilbo thought ruefully, hoping that his nose didn't drip on Thorin's fine trousers.
Then all thoughts of hankies and noses fled as a large hand settled on top of his head, broad fingers sinking deftly into his curls, smoothing his hair back from his face.
"Burglar," rumbled from above and Bilbo rolled his eyes up at Thorin, giving him a sour glare for dredging up that old nickname, "My burglar," Thorin added, softly, and that clarification mollified his prickle of annoyance. "I believe you are the only weakness that I cannot resist."
"Oh, you ridiculous thing," Bilbo grumbled, leaning in to his petting fingers. "You can indulge yourself as you like, so long as you promise to stop trying to pound your head through stones to prove your strength. I don't really require a demonstration."
Thorin leaned down to him, his breath a warm gust against Bilbo's forehead as he pressed a gentle kiss there before murmuring, "As you say."
"I do say," Bilbo sighed, peering up near cross-eyed into Thorin's soft blue gaze. "You're just lucky I found you before you spent the day down there."
"Lucky," Thorin scoffed and he would have leaned back, probably to give Bilbo an unimpressed look that would speak volumes on his opinion of luck. "We make our own luck."
"You may be right," Bilbo agreed and he made a mental promise to help the cooks in the kitchen tomorrow, perhaps offer Balin a hand with his endless scribing, or even stir up a batch of the cookies that Dwalin was so very fond of. When one was courting good luck, it never hurt to tip the odds.