Set some time after the end of the first season. I'm rewatching them all because it's not like I have enough to do with my time as it is, and something in the first episode struck me. This is what happened next.

Aramis had been quiet for most of the evening and it was steadily growing on d'Artagnan's nerves. Athos and Porthos were out of Paris delivering a missive for the king which meant that he didn't have their company to brighten up the near silent dinner he had been forced to sit through, and even the other Musketeers seemed to have picked up on the marksman's mood and were staying clear of their table. It would be worrying if it weren't so annoying.

To start with he'd assumed that he'd somehow offended the man but thinking back he couldn't recall anything that would require this response and either way, Aramis was not one for giving the cold shoulder when he was angry. He often liked to pretend otherwise, but his ire boiled as quickly as Porthos' was known to do.

Then he'd moved on to assuming that something outside of d'Artagnan's awareness had upset him – a death of someone he knew perhaps – but there was none of the usual melancholy the marksman wore when he was wounded in such a way.

The only other option then was that his mind was so preoccupied with some problem or another that he wasn't capable of indulging in his usual conversation. Normally, d'Artagnan wouldn't care but without the other two there to make up for his silence, his evening was turning out to be far more dull than he might have hoped.

The bells had rung eleven before d'Artagnan finally snapped. "Aramis, for the love of god. What's gotten into you?"

Aramis blinked slowly, momentarily looking surprised at how deep the darkness had grown around them before his eyes focussed on the Gascon. "Nothing at all. Why should there be?"

d'Artagnan did his best imitation of Athos' unamused frown. "You've not said a word in hours now. Either say whatever you want to say, or just forget about it, yeah? You're starting to scare me with that blank stare."

"There's nothing you need to concern yourself with. Just remembering something curious, is all."

"Care to tell me what's so curious it's managed to shut you up for so long? It might come in handy one of these days."

The marksman adopted a faux offended expression, but let it fade into an easy smile in the next heartbeat. He paused then, searching for the right words. "Dujon," he admitted eventually.

The name rang a bell somewhere in d'Artagnan's memory but he couldn't immediately place it with anyone of significance. "Am I supposed to know who that is?"

"You met him shortly after you met us. The Red Guard who admitted to Cornet's murder?"

A memory fell into place and understanding lit d'Artagnan's eyes. "He was later found poisoned in his cell, yes? Why on Earth should you be thinking of him? It was almost a year ago now."

"And much has happened since then and now," Aramis agreed readily, smiling gently as his eyes dipped to d'Artagnan's pauldron before returning to his face. "But there's something that's stayed with me even if I didn't stop to think about it at the time."

"Oh?"

"You barely knew us. A few hours prior you had been trying to kill us."

"To be fair, I was trying to kill Athos. You just became collateral damage when you tried to get in my way."

Aramis allowed that with an incline of his head. "My point stands though. We could hardly be considered friends and I'm almost certain that you didn't place one ounce of trust in us until long after that whole affair was over."

"I think I probably started trusting you sometime after you talked me down from killing Gaudet. But yes, when we met with Dujon I didn't trust you. Where's this going? It's not like you trusted me either."

"That's not my issue. The thing is… You had no way of knowing that we weren't going to kill Dujon. The whole point of that act is to make it look convincing and Dujon certainly believed he was under genuine threat, so there's no reason to think that you didn't believe us too."

d'Artagnan was starting to see where this was going, but he bit his lip and let Aramis continue.

"You stood there without protest the whole time. If I had loaded that musket then I would have killed a potentially innocent man right in front of you and you didn't say a word. It's not important now, I know, but it's just… I know you now. That's not the kind of person you are. Not even a little. So why didn't you speak up? I refuse to believe that you went from wanting Athos dead to believing in the honour of the Musketeers in less than a day."

The silence hung over them for another few minutes after that, both of them trying to find the right words to put their thoughts into order. Eventually, d'Artagnan dropped his eyes to the table in something like shame.

"You're right. I should have said something. And I would do now, if I was presented with the same scenario but… Back then? My father had just been killed and I was so desperate for answers. I was just so… bloodthirsty, I suppose. It sounds awful to say but it's the truth. The person that I was in that moment is not someone I ever want to be again; someone who didn't care who around them got hurt, so long as I got what I wanted." His voice dropped very low, so quiet that if it wasn't for the stillness of the night, Aramis would never have heard him. "I'm ashamed by what I would have done in the name of 'justice.'"

Aramis' heart softened in apology, realising his mistake in bringing up a memory that was obviously still so painful. He wasn't usually so tactless. "d'Artagnan, forgive me," he said, reaching out a hand to grip his shoulder. "I should not have asked."

"You have every right to," d'Artagnan said, surprised by the apology. "I barely even realised myself how dark my thoughts were back then. I will never stop being grateful that I found the three of you to pull me out of them."

"We could all say the same of you. Please forgive my intrusion. I had no intention of laying judgement upon you. I simply wondered over the incongruity of your silence. You are not one to sit idle if you think there is injustice before you."

"Nor are you. You didn't deserve the doubt I had for you back then either."

"You had no reason to trust me."

"Reason enough. I had already figured you for a loyal friend and a fierce soldier. It should have been enough to convince me that you wouldn't murder someone in cold blood while they were entirely defenceless."

Aramis gave a lopsided smile. "I could say the same. I know few people who would fight as fiercely as you did to achieve justice for your father. It did you credit, no matter how you may view it."

"I'm not sure I deserve any praise for running in the Musketeer garrison and demanding a duel with the best swordsman in France."

Aramis' laugh was a carefree, light thing. "Perhaps the execution was lacking, but the heart was there. Come, let us talk of happier times. My question is answered."

"I will, if you promise me one thing. If I should ever lose myself like that again, start behaving in a way that ever gives you cause to doubt the loyalty of my heart then… I need you to stop me Aramis. Promise me that. If I should lose my way, you will show me right or you will end me."

From any other person, such a request could be a joke or a mockery, but d'Artagnan's eyes were earnest and Aramis could see the genuine fear that blazed under their soft shine. He would never be able to come back from something like that again, Aramis knew.

"I promise. If you will promise the same for me."

"Of course."

"Then we can rest easily in the knowledge that we have friends keeping us true. Now, let us leave this matter. I should not have brought it up at all. Such morbid thoughts are not conducive to good health."

"Neither is pursuing married women and yet you seem to do little else," d'Artagnan shot back.

Aramis flicked at the arm nearest to him with a scowl, their conversation dissolving into a series of barbs and taunts that were never truly designed to hurt. It was friendship, or brotherhood, and they'd had to fight a long way to get it. To Aramis, at least, it was worth every moment.

I don't really know what this is. Take what you will from it.