A/N: Another fic prompt from tumblr. This one was "There is a thunderstorm and the only comfort for Fili and Kili can come from Uncle Thorin." Enjoy!

The Blue Mountains in late summer were a calamitous place. Though the halls in which the Dwarves lived were cool and dry, they were directly under the perfect gathering-spot for thunderclouds; therefore the summers were filled with the booming and cracking of storms, lightning hitting ancient trees and the wind knocking them to the ground. Even in the mountain halls, one could hear the ever-present sound of tall pines meeting their end on the slopes of the mountain, a dull but resounding boom that echoed through halls of stone.

So it was one evening, unremarkable in most regards, save for the more-frequent-than-usual booming through the halls due to a particularly violent storm. Still, Thorin was used to the sound by now, and he paid it no mind, sitting by the fire and smoking a pipe, perfectly content. It was late, and his duties were done for the day; the fire crackled in the hearth, warming his toes, and his wet clothes hung on a rack, no longer dripping, but still quite soaked. A tree had fallen over one of the entrances into the mountains, and it had taken six Dwarves and far too much time in the rain to safely dispose of it.

A movement in the corner of his eye caught Thorin's attention, and he turned his head; Fíli stood there—all three and a half feet of him—a little wooden sword in one hand and his brother's hand in the other. Kíli was pressed in close behind him, holding tightly to Fíli's hand with both of his own. They both looked at their uncle with forlorn eyes.

"What is the matter, lads?" Thorin said, lowering his pipe.

"It's the giants," said Fíli quietly, padding closer and pulling Kíli after him. "The giants are attacking."

"You have to stop them," Kíli squeaked.

A particularly loud boom echoed through the room at that very moment, and Kíli shrieked, abandoning his usually-safe brother for the even-safer arms of his uncle. Thorin barely had time to set down his pipe before Kíli had scrambled into his lap and flung little arms around his neck, burying his face in Thorin's hair. Fíli looked up at Thorin pleadingly, frowning and holding his little sword against his chest.

"They're getting closer, Uncle," he said, his voice wavering ever so slightly. "I—I brought my sword, but it's only wood, and I don't think it can break stone—"

"There are no giants, lads," Thorin said, furrowing his brow and adjusting Kíli on his lap. "It is just a storm."

"But they live in the mountains, and we live in the mountains," Fíli said. "Big giants of stone, throwing boulders in the rain, bringing down trees and causing avalanches and all sorts of nasty stuff!"

"We're too small," Kíli said into Thorin's shoulder. "Th-they won't even see us if we go to fight them. We'll just get squooshed. You're big, Uncle, and you're the bravest, most toughest Dwarf ever. You've got to go fight them."

"Please," Fíli added, his blue eyes wide.

Thorin pressed his lips together and patted Kíli on the back. The two of them were clearly very sincere in their fears, and he knew he should not laugh at them when they looked to him to make things right.

"I promise you, there are no giants in the Blue Mountains," he said. "It is only thunder and lightning. You will be safe in the mountain halls."

"But Bofur said there were giants," said Kíli tearfully. "He told us."

"Bofur said, eh?" said Thorin, fighting a smile. Of course it had been Bofur. Who else would have told such old myths and legends to his nephews? Dís had scolded him several times already about it. She did not mind the boys being told tales, but they were still too young to know the difference between fact and fiction, especially Kíli, who was only seven. They would believe anything they were told, however benign or frightening it happened to be.

"It was just a story, lads," he said. "There aren't actually giants in the mountains. It is just a storm—nothing more."

Fíli lowered his sword and nodded, looking at his uncle with complete trust in his eyes. But Kíli was not yet convinced.

"B-but I can hear them," he whimpered. "Th-they're throwing trees and rocks… I can hear it!"

"It is just trees falling in the wind, my boy," said Thorin, pulling Kíli away from his neck and looking him in the face. Kíli's eyes were dark in the low light, but even so, he could see tears shining in them. He smiled warmly, and Kíli attempted to smile back, his chin wobbling.

"C-can I sit here with you anyway?" said Kíli.

"Of course," Thorin said, and Kíli settled in his lap immediately, resting his little dark head against his uncle's chest. Thorin wrapped an arm around him and looked down at Fíli.

"Do you want to sit with me, too?" he said.

Fíli thought for a moment and then shook his head.

"I'll be fine," he said, squaring his shoulders and standing up straight. "I can go back to bed."

"All right," said Thorin, nodding seriously. "Good night, Fíli."

"Good night, Uncle," Fíli replied. He looked at Kíli for a moment, pausing; then he turned and left the room. Thorin watched him leave and then looked down at Kíli in his lap. The little one was curled up, his eyes closed and a contented smile upon his lips; Thorin kissed the top of his head.

"Don't worry, lad," he whispered. "You are safe."

A glimmer became visible beneath Kíli's eyelashes for a moment, but then it was gone. Thorin smiled and picked up his pipe.