I genuinely don't know how old Bilbo was when he died. He was last seen at age 131, but I don't know if he died at that age, or what. I like to imagine he lived for 10-15 years in Valinor after getting on the Ship. It also seems that he would've died at some point, being immortal and ancient for a Hobbit.

I just want to point out that Dwalin supposedly dies in the first hundred years of the Fourth Age. For the purpose of this, let's assume he dies a year before Bilbo did.

Valinor was a beautiful place. It was peaceful, fields and trees and rivers surrounding with their soothing sounds, and the Lands were untouched by any evil. Bilbo watched as Frodo healed from his quest to Mordor, a hint of the old glitter returning to his nephew's sky blue eyes. He wished he could say the same for himself. True, his own scars were healing, the guilt fading, but he was feeling weaker and weaker as the days, the weeks, the months stretched on.

He didn't want to leave Frodo.

But soon, he was finding it hard to stand, to walk, and on frightening occasions, to breathe. Frodo watched his uncle with wide, worried eyes and tried his best to help.

"I don't want you to die, Uncle." Frodo said one evening, his hands clasped over Bilbo's.

"Oh, my boy," Bilbo murmured, reaching up to brush back one of Frodo's dark curls. "It will be alright, you'll see. Lady Celebrian will take care of you."

"But-" Frodo began. Then he paused, frowning, at a loss for words. "I'll miss you." he said at last. "You've been like my father."

"And you," Bilbo coughed, "my son. I'll miss you too."

"I wish we were immortal." Frodo said. "Then we would never have to grieve for one another."

"Immortality doesn't guarantee you'll live forever." Bilbo explained gently.

"No," Frodo realised, remembering Legolas' tales of his grandfather, "I suppose it doesn't."

Lady Celebrian was a wonderful Elf. She tried all she could to keep him alive, but one afternoon, she looked down at the weakened Hobbit, regret in her deep grey-blue eyes and apologized for not being able to do so anymore.

"Don't worry, my Lady." Bilbo told her. "I think I'm ready."

Celebrian nodded, lightly squeezing his shoulder. "Would you like to see your nephew?"

"No, not for the moment."

She nodded, her eyes not leaving his. "There is something on your mind."

"I'm just thinking. Do you think I'll see them again?" Bilbo asked.

"The Dwarfs?"

"The Dwarfs." Bilbo confirmed.

"They say Death is an adventure." Celebrian answered. "So, I daresay there is a chance you will."

"I do hope so." Bilbo thought out loud. "I'd like to see them again."

Not one week after Celebrian had informed him that her aid could no longer be relied on, Bilbo lay on his bed, one morning, golden sunlight spilling into the room through the window, casting the room in a warm glow.

He'd lived a long life, far longer than it should have been, and the one thing he regretted (other than his nephew trekking into Mordor to destroy that thrice-damned Ring), was the fact that he'd not been able to share those years with his Dwarf King and the fact he barely saw the Company after the adventure ended.

He reached for Sting. Frodo had brought it in, when he'd started slowing down and falling ill, and had delighted at the look of nostalgic wonder that had appeared o Bilbo's features. Sometimes Bilbo held it and remembered being taught to hold, to fight with and to clean it by various members of the Company. Now he held it, wondering if he actually would see them.

He could feel his heart slowing. He shut his eyes and slowly opened them again. His end was coming. Soon, he would be finding out whether or not he would be reunited with the Dwarfs.

He closed his eyes again and breathed out for the last time.

There was a warm breeze flying past his ears. That was all he remembered before opening his eyes. He stood under a large tree, its huge, thick branches swaying in the wind, green, shining leaves rustling. There was soft green grass under his feet and he stared down at the foliage, before realizing there was something entirely different about his feet.

They no longer bore silvery strands of hair. They were the same coppery-golden colour they were when he had been young. He looked at his hands. Still grasping his letter-opener, they were no longer twisted by age, no longer covered in veins, they were smooth and it was painless to move his fingers. Trembling, he touched his face, gasping and smiling at the lack of wrinkles. He unintentionally disturbed the curls on his head and they flew about in front of his eyes, the same colour as the hair on his feet.

The green waistcoat seemed familiar, as did the earth-brown trousers and the cherry-red coat. He almost laughed to realise that he was dressed how he had been when he'd gone on his adventure all those years ago.

Just as he was contemplating on whether or not there would be anymore surprises, he jumped to hear loud, thudding footsteps.

"Mister Boggins!"

"Kili!" Bilbo stared. It was him. Thorin's nephew, laughter in his blue eyes, dark hair swaying about his face. "Kili!"

Kili barreled into Bilbo, his strong arms crushing the Hobbit into his chest. Bilbo heard more footsteps and a delighted cry of "Our burglar!" and he was suddenly swept up into a second embrace.

"We thought you were never going to die!" Kili said, finally releasing Bilbo. "Glad to see you finally decided to."

Bilbo swatted his arm. "I've got a nephew who's most likely devastated, so don't sound too happy, Master Dwarf."

Kili apologised, but the gleam in his eye betrayed his true feelings on the matter.

"Come on," said Fili. "The whole Company's waiting!"

"The whole Company? What about Bofur and-?"

"No time for questions," Kili told him, tugging onto his arm. "Come on!"

Bilbo didn't know where they were going, but Fili and Kili seemed to, so he pushed away his concerns and his questions and ran with them as they hurriedly led him on.

He was led through thin pine trees, the fresh scent heavenly, through several brightly coloured fields of flowers and suddenly the two stopped running as they reached a path leading to several slabs of rock, a large gap between the two. They made him stand before them and moved him on. He could hear whispering and mumbling and he stopped, making the two princes bump into him.

"What is it?" Fili asked.

"I'm afraid." Bilbo admitted. "What if-"

"Stop 'what-iffing' and go on!" Kili ordered, trying to look serious and failing due to the glittering his eyes beheld.

Gulping a deep breath of air, Bilbo edged forward. His legs seemed very heavy all of a sudden. He could see an orange glow, someone had gotten a fire going, probably Gloin, it was more often than not, Gloin who made the fires, he recalled. As he came into view, there was a rapid silence, broken only by the crackling of the fire.

Of course the silence didn't last long.

Ori was first to greet him, wrapping his arms around the Halfing's shoulders, his soft, woolen clothing brushing against Bilbo's neck. He was very excited to see him, if the hastily whispered words of both Khuzdul and Westron were anything to go by.

When he finally decided to let him go, it was to Bilbo's surprise that Dwalin was next in line to see him. The tattooed Dwarf simply glared down at him and for a moment Bilbo truly was afraid, until Dwalin fell to his knees and enveloped him into his arms, the fur he wore tickling Bilbo's face. He was saying something in such a growly tone that Bilbo couldn't hear it, but given the embrace the Dwarf was holding him in, Bilbo simply assumed it was good.

Balin was all but shoving his brother out of the way, and also gave the Hobbit a hug, this one more gentle compared to the bruisingly affectionate holds that the previous two had given him. When they parted, Balin was smiling at him, like a papa who hadn't seen his child in a long time.

Nori grasped him by the shoulders and pressed his forehead against his, murmuring quiet, softly-spoken words that Bilbo could barely hear, though the few words he did were unmistakably Khuzdul. Nori glanced at him a few times and Bilbo could see the relief and happiness in his dark eyes that told him whatever Nori had been saying, it had been good.

Oin and Gloin swiftly followed Nori, both grasping hold of him as though to make sure he was actually there, as opposed to being a mirage and both laughed and exclaimed how glad they were to see him, feelings Bilbo felt exactly the same way about them with.

Next was Bombur, who grabbed Bilbo's hands, and then changed his mind and grabbed onto the Shireling instead, almost lifting him off the ground in his overjoyed embrace.

Bofur didn't hold his strength back and scooped the Hobbit up in his strong arms, stating, much as the others before had, how good it was to see him and how he'd missed him and that they all had a lot to catch up on.

Bifur seemed hardly able to wait until his cousin finished his time with the Halfling and opened his arms, demanding his own time with Bilbo. He didn't say anything, not even a whisper of Khuzdul, but held onto Bilbo tightly, burying his head into his shoulder.

Then it was Dori's turn. He instantly wrapped Bilbo into his warm arms, holding onto him, before standing back and looking at him with a gaze of something akin to pride, the sort of look only Ori had ever been given.

At last it was time to face the Dwarf he'd been thinking of, missing and dreaming about the past eighty-odd years. Thorin Oakenshield. The King came towards him with the same step Bilbo remembered. His eyes were filled with some strange emotion Bilbo couldn't place and suddenly gentle, calloused hands were gripping his shoulders.

"My dear little thief. You have joined us at last."

"Couldn't stay away." Bilbo joked, though his voice trembled. Thorin was here and no injuries showed on his beautiful face and everyone was well and he was with them. He could feel tears burning in his eyes, despite this, and he blinked furiously, trying to rid himself of them.

Thorin's hands moved and cupped Bilbo's face. The Hobbit blinked again, this time out of surprise. Thorin moved his face closer and Bilbo could see every eyelash, every line, every part of Thorin's features. Then he knew what was going to happen, seconds before their lips met. It was a chaste kiss, innocent and sweet, but could not have been more perfect.

At least until some idiot started wolf-whistling.

Thorin stopped, a small smile on his lips, and stepped back. "Sit with us." He said, holding out a hand for Bilbo to take. "We have much to discuss, I'm sure."

"What is this place?" Bilbo asked.

"Well, it isn't Mahal's Halls, that's for certain." Dwalin answered.

"Why are you not there?"

"Who knows?" Balin said. "Perhaps He knew we would want to see you before He allowed us in."

"Then, what happens next?" Bilbo wondered.

"Does it really matter why we're all here?" Bofur asked.

"No," Bilbo answered. "But this is all very confusing."

"That's life, lad." Gloin said. "Or death. Whatever you call this."

"What are we all doing here?" Bilbo asked suddenly. "I don't recognise it."

"As Gloin said, it's a new place," said Nori. "'Tis for our own curiosity."

"Tell us, burglar," Thoirin asked, "how would you feel about going on another venture?"

Biting back a grin remembering his first response, Bilbo looked up at his once-lost love and all his old friends. "I think I'd like that."

Thorin placed a hand on his shoulder, unashamedly smiling. "I am glad, ghivashel."

Letting his own smile show, Bilbo murmured, "as am I."

And then they all spent their afterlife catching up with each other and exploring the mountains and woods and things in the place it was they ended up in. And when Frodo eventually died, he met up with them all and finally met his honorary cousins, Fili and Kili.
And so the Company of Thorin Oakenshield gained its fifteenth member.

The End.