"Shall we go out today or stay in?"

Wooyoung glanced at the mist outside the window. London had returned to its cold and wet ways and the outside world looked less than attractive. Like one massive puddle, it sat around them with its wetness.

Wooyoung dropped his unwilling head back on San's chest. Chuckling, the man buried his fingers in Wooyoung's hair once more.

It was Wooyoung's last day in London. He planned to leave in the evening at last and return home relatively on time so they could squeeze in as much work as possible before San would come to the institute. His wish to stay with San as long as possible contrasted with his need to finish his work. Yongguk could wait a while longer.

Yet Wooyoung knew that delaying his departure further wouldn't get him anywhere. He would only want to stay until all eternity.

This time, at least, he had the comforting knowledge that San would be with him soon. There was no need for a long time of waiting between now and their next final meeting. Their step in Munich was more of a safety precaution and then, after so much waiting, they got all their time to themselves. The card that Wooyoung would bring San with their address in the future written on it would get decorated with every glittery pen and childish sticker Wooyoung could find.

"Let's just do nothing and drink tea today. I don't want to see anything else but your face today," Wooyoung grumbled into San's neck. Amused, the man tilted his head to look at Wooyoung.

"Just my face?" His teasing undertone carried a faint disappointment.

Wooyoung gently whacked his skin.

"You're insatiable," he complained without fire behind it. Not as if that time wasn't wisely spent.

"You'll have to blame that on yourself. How am I supposed to resist when I have you gorgeous person here right in my arms?"

Buttered up by San's charming voice, Wooyoung smooched a kiss against the man's neck before he pushed himself up. The covers slipped from his naked shoulders as he stretched. San lingered on the sheets, enjoying the view while his fingers caressed Wooyoung's thighs.

They finally got out of bed long after morning had passed. San's open shirt proudly showcased the pendant on his skin.

As the two men sat in the kitchen to fuel their bodies with tea and some soup that Wooyoung whipped onto the table on a whim using everything he found in the cabinets, the mood was sombre. They bickered as before, but the looming threat of Wooyoung having to leave soured their mood. None of his jokes could quite lift the heaviness of San's gaze.

They spent their day in peace, as Wooyoung had suggested. Just leaned against each other; they read and quietly discussed trivial things. Neither work nor their parting had to be mentioned.

The sun raced over the skies as if it wished to see them suffer. By the time it set behind the buildings, Wooyoung sat with his head buried in San's shoulder on his lap on the couch. They clung to each other stubbornly, as if that would defy Wooyoung's own rules.

"You need to go, Woo," San reminded him with a whisper against Wooyoung's scalp. He had already packed Wooyoung's things an hour ago and Wooyoung dodged the sight of them next to the door leading outside.

Lingering just made their goodbye so much harder.

As much as Wooyoung had hoped to frolic about this goodbye since it would allow them to meet so soon, he now found it incredibly difficult to wait the last few days until it was time. Time never dragged on for so long.

"I hate to leave you waiting... Now you will look forward to meeting me so much. Will know that I exist already somewhere but that it's unsafe to visit before the date I will tell you since I wouldn't recognise you."

"By the time I visit, you will have studied immortality a lot and will have a lot of precious answers for me. After so many years waiting two centuries for the sweet payoff of your dedication and wisdom is nothing," San assured him. His voice was ever so understanding of Wooyoung's upset.

"I will study extra hard for you. Then my boss will have no other choice but to let me take days off so I can spend them with you." Pouty, Wooyoung burrowed deeper. San's rich chuckle both warmed Wooyoung's heart and reminded him how unfair it was that they had to part.

"I look forward to that."

When Wooyoung sat up, San pulled him in to leave a lingering kiss on his forehead. Comforted in his sulking, Wooyoung finally stood from the man's lap to leave.

San accompanied him to the door and held his hand as Wooyoung searched for words.

"Munich on the last day of March in 1950," San repeated the words he had memorised by heart already. Wooyoung nodded shyly.

"At the town square or however much we find of it," Wooyoung added.

San's fingers slipped into Wooyoung's hair to hold his skull lightly as they kissed. Yearning and the promise to see each other again, to finally, finally end this long history of goodbyes conveyed in their deep kiss.

When it ended, Wooyoung gave a cute wave at San and turned to leave. San smiled at him until the door closed between them.

Wooyoung was back in the institute. He had never felt as if he had been gone for so long.

The walk through decontamination and changing his clothes was no more but a routine nuisance to Wooyoung. Three days. He would go check on San in three days. No matter if Yongguk and Seungyoun screamed at him to take breaks in between and let his body sort out any weird bacteria he might have come into contact with. If Wooyoung missed San so much, he wouldn't want to think about the weight of San's yearning.

Yongguk sat in his office with his hand in his cookie box when Wooyoung marched in. In the first moment, Yongguk looked caught before he remembered he had every right to be eating cookies and continued the movement.

"Hey. How are you?"

Wooyoung's upset must have shown on his face for Yongguk to ask like that. With a groan, he dropped in his favourite chair in the office.

"Good and I bear much great news. Just salty because I had to say goodbye to San."

Yongguk's empathetic smile had Wooyoung reach for a cookie, too. The chocolate chips brought his mood back up.

"You can meet him again soon. Tell me what you found."

Wooyoung recapped their conversation with Jongho in as much detail as possible. He stressed how San had mentioned not knowing how he had become immortal as well, connecting to Jongho's suspicion that this immortality wasn't man-made. The enlightenment stood in their way of developing their own scientific way to turn their people immortal, but Yongguk was just intrigued to find out about San's story.

After their talk, Yongguk handed Wooyoung a thick folder with his accumulated research and all the reports he had written. Yongguk had added his own thoughts and provided further sources for Wooyoung's reading. With his folder in tow, Wooyoung dragged himself up into his office to start with work already. The faster he got it done, the faster he could finish his part of this job and invite San over.

Yongguk had stressed once more that despite San's involvement, their job came first. With a begrudging sip of his coffee, Wooyoung slapped open the folder to get to work.

Since he was exhausted from his trip, he only over-viewed his work so far. The many days he had spent in different times connected through the tales about immortality. He neatly set the interviews with his friends aside and skimmed the titles of Yongguk's extra sources. Most of them fit something the various people had told them. After sorting them into their respective piles, Wooyoung grimaced at the way Yunho's pile barely got any comment. The poor man.

Wooyoung didn't need to write an end report anymore, just his conclusion of what they could do about immortality. His part was only the base work and other people in other institutes would have to develop whatever cure against ageing he came up with. He gnawed on his lip as he sat at it. His room was dark apart from the one lamp on his desk he had lit and his pen weighed heavily in his hand.

If he wrote something about the Philosopher's Stone or the Holy Grail, the people taking the case from them would know to pick an alchemist route and experiment with biological components that a team of experts could research. However, since San was their living example of how immortality came to be, Jongho's words still rang in Wooyoung's head. Not man-made. Accidental. Perhaps a blessing by the gods? Or rather something else if they ignored religious beliefs.

Wooyoung exhaled.

Ultimately, he pushed out his duty to finish the research to another day. He didn't want to make the judgment that any attempt of human influence on life was in vain. After all, he had been sent to prove that theory wrong.

Perhaps they searched in the wrong area. Even if San existed, the true means of immortality for humans might lie beyond. In the far future, or maybe in the far universe.

Wooyoung left his papers as they were so he could return the next day as he picked up his bag. The pressure of ending this long job that had busied him for over half a year weighed heavy on his shoulders. Yongguk would fact-check him before their studies went anywhere, but Wooyoung didn't want to cause disillusionment.

Not when he had an immortal by his side.

Wooyoung's ambition to discover something huge contrasted with his care for San. He had promised the man not to dig into his past to find out what had happened to him back then. Yet, Wooyoung couldn't help but hope the man would allow him to go back and study him once he got a full grasp of their work.

San was the key. But if Wooyoung wanted to keep his secret for as long as possible, he would better write that their search for immortality came up empty.

With a sigh, Wooyoung shut off the light and locked up his office as he left. The museum was closed by now and as Wooyoung travelled through the dimly lit corridors in the night; he ordered himself some food to enjoy at home. Even when that was not the place he wanted to be at.

Home had become an abstract concept for Wooyoung. He felt welcome in the past, although never quite at home. But neither did this time and this flat feel like home. The lines blurred until he couldn't tell anymore where it was he was most comfortable in.

Wooyoung left the building and walked to his flat despite the late hour. His mind was too occupied to want to be distracted by traffic and people.

Back in his yawningly empty flat, Wooyoung picked up the food that the drone had left in front of his door and sat down on his couch. Some nonsensical TV program filled the emptiness in the background as he ate.

When Wooyoung crawled into bed after a long shower, he couldn't sleep. He kept tossing and turning, finding no spot pleasant enough, and all of his pillows unsatisfactory in their give.

It took him a while to understand that he couldn't sleep without San and that the comfort the man's body spent against his was missing.

Wooyoung got a few displeasing hours of sleep in before he gave it up the first time he opened his eyes and saw the sky greying outside of his window. With dark circles under his eyes, he left his room to sit on the couch again and watch some TV.

Later, he fell asleep once more since the backrest of the couch came as closest to a body behind him as it could get. He missed Seungyoun's enthusiastic message about meeting after work to talk and drink a coffee together. Wooyoung was thankful for the sleep as he dragged himself back to the institute a few hours later to do some more work and to distract himself from his yearning for San.

As long as he finished his statement in time, Yongguk couldn't complain if Wooyoung jumped right back in time to meet San. Since he stayed in his office downstairs, he couldn't complain about the many cards Wooyoung wrote whenever his mind drifted off the long texts on his desks to find the most beautiful design to relay San their address and meeting time.

On the second day after coming home, Wooyoung handed in his work. The bottom line read 'So fat, the extinction of the human ageing process is impossible to perform by any known resources. Further biological studies needed.'

By that, his work was done.