Here's some of that backstory you've been waiting for... though not all of it... ;)
Disclaimer: I do not own the BBC's The Musketeers
Earlier that same day, d'Artagnan had been sitting at breakfast with Athos and Porthos awaiting the medic's arrival. At first, Aramis' absence hadn't been particularly noticeable, but as the hour ticked on and the time for morning muster approached, Porthos began to send more fugitive glances towards the entrance of the garrison.
"Perhaps he's in his rooms?' d'Artagnan suggested, as the courtyard got busier.
"I checked on my way past," said Porthos, with a shake of his head.
"Then perhaps at another's rooms?" Athos added coyly, with something of a knowing smirk on his face.
Porthos sighed.
"That man is going to get a rollickin' from the Captain."
"I doubt that would concern our friend," Athos said with a slightly amused expression on his face. "He can basically recite the dressing down verbatim."
"That many times?" d'Artagnan asked.
Athos didn't answer, but the upward twist of his lips gave d'Artagnan all the confirmation he needed.
Treville arrived at that moment, and the three men rose to stand with the rest of the men, and all the while Porthos was muttering under his breath.
If Treville noted Aramis' absence, he didn't make comment on it, and he set Porthos, Athos, and d'Artagnan to duties and training in the garrison for the day. D'Artagnan set to work drilling some of the newer recruits in their sword-craft, all the while passing the odd look towards the garrison entrance and, even more so, watching out for Porthos, who kept finding excuses to leave the armoury to check the courtyard for his absent friend.
As midday arrived, d'Artagnan called a halt to the training, looking towards the entranceway anxiously for Aramis, who had yet to make an appearance. By now, both his brother and he were getting worried. Treville came down the stairs and whistled to Athos, who was sitting outside the armoury and sharpening the weapons. He walked towards the Captain with an expectant look on his face.
"You want us to go looking?" he asked.
"Find him," Treville nodded. "And let's hope he's simply forgotten to rise with the morning sun in whichever bed he took for his last night."
"Aye," Athos agreed, jerking his head a little to indicate that Porthos should leave his post.
"We can go?" Porthos asked.
"Let's bring our boy home," Athos confirmed.
As the clock struck twelve, the three brothers set out in search of their fellow friend.
"So where to first?" d'Artagnan asked.
"Well, I last saw him at the Goose & Hare so let's start from there shall we?" Porthos said.
The three of them wandered towards the tavern in question and ducked inside. During the day, the place was relatively quiet. A few regulars were still about but otherwise there was only the bar keeper, who was wiping down the sides and restocking his shelves.
"Good afternoon, Monsieur," Athos approached the bar.
"What can I get you fellas?" the bar keeper asked.
"Actually, we're looking for someone," Athos began.
"My friend, who I left sitting at the corner table last night," Porthos added in.
"Oh, yes, I remember," the bar keeper nodded. "He left maybe an hour after you did. Got into a scuffle of some sort with the another fella. They took it outside, so I didn't get involved."
Porthos frowned at the response.
"My nights are busy," the bar keeper interceded. "If I got involved in every fight that goes on outside my doors, I'd never have any time to run my bar."
Porthos still looked disappointed by the answer, but didn't say anything else. He pushed himself off the edge of the bar and headed back towards the door.
"I saw your friend brush off the other guy," one of the regulars interrupted their exit from where he sat near the door. "I didn't catch what he said, but when he departed he headed off towards the edge."
The Goose & Hare was near the edge of Paris, so if Aramis had turned to his left as he exited the tavern, he'd have been walking towards the city limits.
"Thank you," Athos nodded to the man and dropped a coin for a drink down on his table for the information given.
Once outside, the three men stood and checked their surroundings, before moving off.
When they reached another tavern, Porthos made to stoop inside, but d'Artagnan hesitated.
"How about I go ahead towards the city limit?" d'Artagnan suggested. "We might track him down faster if we take different routes."
"You think he left the city?" Porthos asked doubtingly.
"Probably not," d'Artagnan responded. "But if we drop into every tavern we might not get the answers we want for some time. I'm merely suggesting that I jump ahead a little, and I might rumble up some answers. Splitting up would make the search faster."
"He's not wrong," Athos agreed. "How about you and I check alternate taverns, and d'Artagnan can check the road. We'll see what we can drum up."
Porthos grumbled his assent and ducked through the low sitting door arch while the others set off ahead of him.
The next tavern owner had not seen his friend, but the one after recognised the description. Apparently Aramis had been accosted once more by the unknown man the first bar keeper had spoken of. There had been some sort of altercation between the two which had resulted in Aramis running out and leaving both a beautiful woman and his unpaid tab behind. Porthos begrudgingly paid the money his friend owed and then set back out in search for him with worry worming away in the pit of his stomach.
A short while later he reconvened with Athos, who had found only a report that a man fitting Aramis' description had run through this way in the early hours of the morning. Porthos worriedly told Athos about the man that appeared to be accosting their absent friend, and then they both set off to follow the Gascon's trail, in the hopes that he had more luck in locating Aramis.
As they walked towards the city limit Porthos couldn't help but notice how Athos' hand had dropped down to rest on the hilt of his sword. And Porthos, himself, had loosened his main gauche in his belt.
