Thorin peered into the encroaching shadows, stars still dancing in his vision from the abruptly vanished firelight. In the previous scuffle the first time they confronted the elvish revellers, the company had eventually been able to find one another. Thorin wondered if their second plan, for him to go first so as not to surprise the elves into running away, might have been foolish. It would not shock him if the whole thing had been a scheme by the blasted creatures to draw them off the path, hungry and desperate as they were, and then separate them.
So here he was, stumbling in the pitch-black, calling out Dwalin's and Balin's, Fili's and Kili's and Bilbo's names in succession, to no avail. There was no answer, no sound to indicate he was anything other than hopelessly alone, and helplessly lost. He had no way of knowing if his fellows were safe, or even alive. As far as he could tell, they were far away, way out of earshot.
Standing still would do no good. Sitting on the ground and hoping someone might stumble across him in the dark would do no good. So Thorin turned until he had what he felt might be the right direction, and began to walk.
It slowly and ominously occurred to him as he trudged along that something was wrong. The forest was as forbidding as it had been since they stepped in, and he had the same conflicting feelings of being both utterly alone and also followed by thousands of eyes, but this was something else. Something new, or changed. Something in the weight of his own step.
Thorin checked to make sure he had his axe. It was there. His heavy coat, his belt, even the light but assuring weight of the key around his neck, all was where and as it should be.
Except for the sword.
Thorin stopped dead still as he drew what should have been Orcrist. It wasn't. The scabbard and the hilt were the wrong shape and width, and Thorin was dumbfounded as to how he could have failed to notice up until now. At the very most, it could only be half Orcrist's size. He must have picked up the wrong weapon the first time they tried to talk to the elves. What and who's was this sword then, if it wasn't Orcrist? A dagger, rather than a sword. Well-made, but not dwarf-made. He had no way of having acquired it from one of the elves, they had all vanished as soon as he stepped in amongst them. He couldn't recall any of the dwarves in the company carrying such a weapon. He ran his fingers over the flat of the blade. Odd. The smooth swirling pattern on the blade was the same as Orcrist's, but …
Oh. He couldn't recall any of the dwarves in the company carrying such a weapon, because no other dwarf in the company did carry such a weapon. But Bilbo did.
This was Bilbo's sword.
Thorin sat down, exasperated, and rubbed a hand over his face. He had fought with small swords before. Angry as he was for having lost Orcrist and picked up this tiny dagger, that wasn't a problem. If he was confronted by a denizen of the forest, he would be able to defend himself. But if Bilbo hadn't picked up Orcrist when Thorin picked up … whatever this toothpick was called, then Bilbo was weaponless. And even if Bilbo did pick up Orcrist, it was considerably heavier than his own sword, and not double-edged. He had seen the way Bilbo swung that small sword about when he had come rushing to Thorin's defence, what felt like so many months ago. He doubted Bilbo was capable of wielding any weapon properly, let alone Orcrist.
Thorin pushed the thought to the back of his mind. He would find the others, or at least try, and they would sort out the business then. He stood and continued to walk, now even more troubled than before, which was quite frankly extremely troubled, so much so that he did not notice in time when the ground began to give way. A soft rotted plank of wood gave way under his foot, and he tumbled head-first and rolled down a decline covered in dead leaves and dotted sparsely with roots and thin trees. He tried to grab at the skinny branches, but he either missed or they came off in his hand. When he saw what was at the bottom of the decline, Thorin tried to claw his way to a stop, but not quickly enough. He hit the water, and half a second later, Bilbo's sword thudded along the decline after him and landed on his face.
AUTHOR'S NOTE: I have no idea if Thorin lost his axe in the goblin's cave, so I included it here just in case.