"Pem á kal-miel." Shepard eyed Mordin suspiciously.

Mordin calmly interlaced his fingers, elbows on the table in front of him - the picture of innocence. "Rohk á miel-an-kal."

"Van á kal-miel-an."

"Rohk á kal-miel."

"Damn it," Shepard muttered as Mordin's knight icon replaced her now-captured queen.

"Covus," Mordin reminded her, and she made a face.

"Sehk, sehk," she grumbled.

"You agreed," he informed her casually, leaning back and surveying the Citadel park they were in - complete with nearby pond - as she rolled her eyes and examined the board.

"We haven't even been playing for five minutes, and you've already got my queen," she told him. "At least let me accept my impending defeat in English."

"Covus getting good, though!" Mordin leaned forward again and placed a hand on the board. "Covus."

Shepard gritted her teeth, then thought hard. "Laroh vudiru yia rae ve English."

"Vudiray," Mordin corrected, and Shepard groaned again and thunked her head on the table.

"What was wrong with that?"

"Wrong modifier," Mordin explained, tapping his fingers idly on the table, amused. "'Vud,' allow, 'ir,' conjugation, 'ay,' salarian modifier."

"Would I still use that? I thought that was for two salarians of different nations," she commented, raising her head enough that she could peek at him with one eye.

"Also of use with salarians in general. Considered rude to use 'u' modifier for salarians - 'u' only used for non-salarians."

"Oh." She winced. "Oops. Sorry."

"No trouble," he told her gallantly. "Learning! And no," he said with a surprisingly cheeky grin from someone typically so reserved. "Speak Covus."

"Fine. I mean," she corrected hastily, "uh… Shat?"

"Wrong word," he told her, and she thunked her head on the table again. "Shat means 'okay' as in 'I am okay.' Use 'teh' instead."

She glared. "Teh," she muttered finally, viciously.

"Mordin Solus!"

Shepard jumped; Mordin merely blinked.

"Mordin Solus, bemaha?"

"I'm putting my translator back on," Shepard said quickly, and pinched the piece of technology clipped to her earlobe.

Mordin sighted the speaker walking across the park walkway. "Padok Wiks," Mordin said neutrally, standing.

A tall salarian, armored, his grayish face lined with red, approached with a drawn expression. "Mordin Solus."

The two stood, staring, neither moving a muscle. Shepard awkwardly glanced from one man to another, both their faces unreadable.

Finally, the other salarian - Padok, Mordin had called him? - held out a hand, a wide grin blossoming across his face. Mordin's face broke into a more relaxed smile and the two clasped forearms.

"Padok," Mordin said, more warmly this time. "Surprised to see you here."

"I'm only on the station for a day. Layovers," he said sheepishly. "I'm surprised to see you! What happened to Omega?"

If Mordin was surprised the other salarian knew about Omega, he didn't show it, and didn't miss a beat, gesturing to the Commander. "Recruited. Left clinic in hands of former assistant. Good kid."

"Good. Though I fear Omega may not be the best place suited for a kid - unless he's a former… soldier?" Padok guessed.

Mordin didn't answer, sidestepping the question. "Clinic in good hands," he told the other salarian.

"All right, all right. Are you going to introduce me?"

Mordin inclined his head. "Padok, Commander Shepard of the Alliance Military and Special Tactics and Reconnaissance. Shepard, Pehwera Padok Wiks á Shehz Lorak Boh."

Her translator didn't seem to want to translate that; Padok understood it perfectly, though, as he did a double-take, and swallowed.

"Well," he said nervously. "Uh - "

"Knows about my work," Mordin said airily. "Shepard, translator."

"What?" she asked him.

"You agreed," he admonished, and she gaped at him.

"But - !" she began, pointing at Padok, but Mordin held up a finger.

"Agreed to afternoon in park," he said primly. "Translator off." He then tilted his head toward Padok. "Also, he speaks English."

"Translator?" Padok asked blankly, and Mordin nodded.

"Teaching her Covus. Agreed to afternoon speaking Covus - without translator," he said, eyeing the Commander, who sheepishly pinched the translator at her earlobe.

"Wow," Padok said approvingly, switching near-effortlessly to English. "Not many humans are so brave to try that."

Shepard listened with interest as his grammar became slightly stiffer - and his accent changed when her translator switched off, too. Instead of Mordin's careful, precise enunciation, Padok's had the breathy quality of Covus, with R's not rolled, but instead with tongue flicked against the roof of the mouth, and his b's almost indistinguishable from v's. "You have an accent."

"Of course I do," Padok told her matter-of-factly; he looked at her oddly. "Why would I not?"

"Mordin doesn't," she told him.

"That's Mordin ," he said, as if that explained the matter; at her blank look, he shrugged and gave a half-smile. "Don't tell me he hasn't told you about his interest in language."

"He has."

"He considers correct accent to be part of the language," Padok said, waving a hand, as if the idea were preposterous. "It's not, but - agree to disagree!" he said quickly, raising his hands, as Mordin turned toward him.

"Correct pronunciation important," Mordin said mildly, and Padok huffed.

"We don't always agree," he told the Commander. "Pronunciation does not always mean you have to mimic accents. Accents vary by region," Padok told Mordin, then glanced at Shepard. "Is he having you mimic Covus accents?" he asked suspiciously.

"Sao," Shepard told him. "No, just repeating after him." She leaned her elbows on the table, head craned up to look at the two tall aliens. "You two want to sit down?"

"Ah. Can continue playing," Mordin said happily, and sat. Padok stood there awkwardly until Mordin glanced up. "Can sit," he told him.

"Right," Padok said awkwardly. "He is teaching you chess, too?"

"Sehk," Shepard groaned. "Keeps thrashing me at it." She made a face as Mordin drummed his fingers on the table and gave her a light smile.

"Covus," he reminded her as Padok pulled a chair over.

"He's quite the stickler for this agreement, isn't he," Padok observed, sitting down gingerly, as if the chair might bite him. Shepard nodded.

"Yeah, he is - I mean, uh, sehk, bemkeu. I mean, bemkeay." She grumbled. "Ugh. Modifiers."

"He's teaching you modifiers?" Padok asked, surprise clear on his face. "That is, uh, complex for a human."

"Sehk," Shepard agreed sourly. "But I asked for it, didn't I."

Mordin was chuckling. "Did indeed ask me to teach you," he noted.

"So how do you two know each other? I mean," she said hastily, "uh - qah kurak meaayak?"

Padok slowly grinned. "Should I reply in Covus?" he asked, and Mordin shrugged.

"If you like. Though may be good for you to practice English," he remarked.

Padok rolled his large eyes. "Only you," he accused, "see the need to learn so many languages."

"Language influences thought," Mordin said matter-of-factly.

Padok sighed. "You could be right," he admitted begrudgingly. "English is an odd one, though. Why not something more useful? Palaven?"

"English is useful," Mordin told him. "Humans - fastest rise to power in galactic history. English a prominent language amongst them."

"Are you going to answer my question?" Shepard asked, grinning, and Padok crossed his arms and leaned back in his chair.

"Sorry. As Mordin said - Shehz Lorak Boh."

"Special Tasks Group," she guessed, and Padok nodded; Mordin inclined his head. "Did you two work on the same projects…?"

The two salarians exchanged glances; some form of agreement passed between them in an instant.

"Yes," Mordin said, and moved his knight, switching off the board's verbal input in favor of manually moving the piece.

"We are not discussing details." Padok's voice was suddenly hard; Shepard looked at him, mildly taken aback.

"I'm not asking you to," she stated honestly. "I know it's not something to bring up in casual conversation." She leaned forward and moved a pawn one space forward. "I'm just trying to gauge how well you two know each other."

"Friends," said Mordin at the same time Padok said "Well…"

The two salarians exchanged another glance.

"We were - " Mordin began at the same time Padok said "When we - "

They both sat back.

"You go," Padok said, gesturing with one hand.

"We were both on same project, but not same application," Mordin said, and slid another pawn forward. "Worked on different aspects."

"Mine was mostly theoretical, while his was more practical," Padok agreed, throwing one long leg over the other and jiggling his foot. "I daresay that is all we should say."

"You two not always get along?" Shepard asked, and they exchanged glances again.

"No," Padok said dryly. "In fact, if I recall correctly, I once punched him in the face."

Shepard paused. "You punched Mordin in the face," she repeated.

"Disagreement over evolution," Mordin said shortly, and tapped the chess board; Shepard hastily moved a pawn, then sat back.

"You punched Mordin over evolution."

"We're not getting into it right now," Padok said with a wary glance at Mordin. "I don't think we agree on it even now."

"Fine by me," Shepard said, and concentrated on the board. "How do I even win without a queen?"

Mordin nudged her with his foot. "Covus," he reminded her yet again. "And possible. Done it before."

"I know you have," she muttered. "Fine - I mean, teh, teh."

"How do you two know each other?" Padok asked curiously.

"Recruited," Mordin said. "Mission."

"Against the Collectors - ugh, I mean, gatiak Tudehn."

"Collectors?" Padok asked, interested. "I thought many people thought they were a myth."

"Real," Mordin assured him. "Working against bio-threat right now."

"Bio-threat?" Padok leaned forward. "Care to share? Oh, that rhymed! Doesn't sound quite as pretty in Covus. Waa dahl. 'Care to share.'" He mulled the words over. "Anyway."

Mordin glanced at the Commander, who didn't catch the cue until after she'd captured one of his pawns; when she saw him looking at her, she gave a curt nod.

"Lateral gene transfer," Mordin stated. "Collector swarms use paralytic agents to neutralize enemies. Trying to find way to counteract."

"What does that have to do with lateral gene transfer?" Padok asked, curious, and Mordin leaned forward and rested his chin on his interlocked fingers.

"Multiple approaches," Mordin said, and moved a rook forward. "Would ideally like to prevent paralysis through form of genetic modification; vaccine to make people resistant to paralysis. In reality…" He sighed and watched the Commander as she moved a knight perilously close to his own queen. "In reality, unable to synthesize. Ended up hazardous to too many groups for viable use."

"Is the paralysis part of the gene transfer?" Padok wanted to know. "That sounds awful."

"No - paralysis temporary," Mordin assured him. "Idea was to use genetics to create countermeasure. Make body create counter-chemical."

"That would be really complex for multiple species," Padok said slowly, and Mordin nodded.

"Part of reason it didn't work. In reality," Mordin added, "was able to create 'invisibility vaccine.' Make people appear as species they are not to Collectors."

"That's clever," Padok said approvingly, though Mordin shook his head.

"Requires boosters," he said sourly. "Not very efficient."

"Never one to accept mediocrity," Padok said with a grin.

"Check," the Commander said suddenly; Mordin glanced down and smoothly captured the offending bishop.

"Covus," he admonished.

"Fine. Mnuy."

"Morai," he told her, and they continued to play.

"This swarm paralysis," Padok asked suddenly. "What does it do?"

"Occupies functional sodium channel," Mordin answered. "Varies species to species - human most difficult."

"Ouch. That's a complicated one," Padok said, wincing. "And there's no way of just blocking it some other way?"

"No antidote known," Mordin confirmed. "Tried any I could find."

"And I trust you were thorough - you do not do anything halfway," Padok mused. "No finding anybody that's immune, either?"

"None found."

"Does this work the same way in all species?" Padok asked speculatively.

Mordin frowned at the chessboard and moved a pawn to capture another pawn. "Sodium channel blocker."

"And I'm guessing there's no time to synthesize some blocker to block those channels."

Mordin paused. "Trying to prevent paralysis, not cause," he stated.

"I'm not saying occupy the channels. I'm saying block it. Like…" Padok hesitated, searching for the English word, then switched back to Covus. "Ka dahz heit biy."

Mordin continued frowning; Shepard let the two of them continue the conversation, playing her chess in silence. "Like a puzzle piece with a hole in it," Mordin repeated in English, and Padok snapped his fingers and pointed.

"Yes! Puzzle. Sorry. Could not think of the word."

"No antidote known," Mordin repeated. "Could not find one."

"Is there any chance someone could end up immune?" Padok asked, but Mordin shook his head.

"Collectors focus on human colonies; leave nobody behind," he said. "Not enough warning."

"Ah." Padok was silent for a moment, then stated, "What if the Collectors are immune?"

Mordin's head snapped up. "What?"

Padok grimaced. "I'm just saying!" he said defensively, but Mordin shook his head.

"No," Mordin said. "No - haven't considered that. Always assumed Collectors merely not targeted."

"We need a sample of a Collector," Shepard interjected, eyes wide. "So you can test it."

"Could try sample taken from items already in possession," Mordin said, leaning on his interlocked hands again. "Collector carapace from previous fights; remnants on armor, weapons." He eyed Shepard. "Know you bashed in one's head with a pistol," he remarked.

"Because it almost broke my arm," Shepard muttered. "But explain this to me - because I don't understand a lot of what you're saying - if we find a Collector that's immune, what does that mean?"

"Means can possibly synthesize actual effective vaccine," Mordin said, his speech becoming more rapid. "How to synthesize? Ah - monoclonal technique," he mused, standing and beginning to pace. "Likely that non-Collector species not able to produce protein; will need to find substitute, but…" He nodded. "Primary target TTx-r sodium for humans - humans most difficult."

"Always strange watching him think," Padok remarked, crossing his arms underneath the armored band across his concave chest.

"Stranger for me, maybe, because I can't ever understand him," Shepard said, grinning. Padok grinned back.

"Prevalence of TTx-r sodium channels in central nervous system possibly counter-intuitive due to - Padok!" Mordin said suddenly. "Autonomic nervous system - not affected. Ideas?"

"Selective inhibitor," Padok replied, and Mordin went back to muttering and pacing alongside the small pond.

"What?"

"He said the autonomic nervous system isn't affected by the paralysis - breathing, heartbeat, that kind of thing. Then he asked for ideas on why, and I told him possibly a selective inhibitor - which would complicate it greatly, but he's used to working on complex projects," Padok told her. "Selective inhibitors are exactly what it says - they prevent things from happening, but selectively. Hey, Mordin?"

"Yes?" Mordin paused.

"Have you tried searching for things that have similar mechanisms of action?" he asked, and Mordin nodded.

"One of first things tried. Callerd toxin, dilusts, dicatine, even awphalinems."

Padok sat back. "Those are all from other places, though," he realized. "What about things specifically from Earth, if they're going after humans?"

Mordin nodded slowly. "Sodium channel blockers…" he said. "Intracellular, not much - lidocaine, anticonvulsants…"

"Extracellular?" Padok asked.

Mordin suddenly spun on his heel. "Tetrodotoxin, perhaps. Toxin in some Earth sea life," he said, his speech continuing to speed up. "Technically observed in fish first, though actually produced by certain infecting bacteria." He waved a hand, continuing to pace along the pond - faster and faster. "Binds to voltage-gated sodium in nerve cell membranes."

"Just like the swarms," Padok noted when Mordin stopped to inhale, and Mordin nodded, a quick and jerky movement. "Mordin, come away from the - "

Mordin didn't hear him. "Could possibly use tetrodotoxin to synthesize stepping-stone antibody…" He spun on his heel and marched back. "Monoclonal antibody already synthesized works on tetrodotoxin and anhydro-tetrodotoxin, could give clue to synthesizing for other species with differing channel shape - "

"Check mate! I mean, mnuyahk!" Shepard said suddenly, smacking her hands on the table; Mordin jerked, surprised, spun on his heel -

- and promptly lost his balance directly next to the pond, and landed with a splash.

Padok burst out laughing and darted forward. "Mordin!" he called.

Mordin surfaced, coughing, and thrust a hand out; Padok grabbed it easily and hauled him out onto the metal park walkway. "Thank you," Mordin croaked, gesturing with his thumb from his chin.

Padok froze. "Uh," he said.

Mordin also froze, looking mortified. "I mean, thank you," Mordin mumbled, redoing the gesture - this time with his fingertips from his chin. "Means - er - thank you in American Sign Language."

Padok spun. "Is that true?" he demanded of Shepard, who yelped.

"I don't know! I think so? Why? What's so funny?"

Padok had begun to chuckle; then laugh; then he laughed even harder, wheezing for breath. Mordin stood to the side, sopping wet, looking somewhat embarrassed.

"Padok? Mordin? What's going on?" Shepard asked warily.

"He just accidentally told me to go fuck myself," Padok gasped, wiping one eye. "He mixed up 'thank you' and the Covus sign for 'go fuck yourself!'" He giggled, turning to Mordin. "I know we're not always friends, but that's no way to say thank you!" he guffawed.

"Yes, yes, laugh all you like," Mordin said flatly, readjusting his sleeves. "Apologies."

"No harm done," Padok wheezed.

Shepard had begun to chuckle. "That's quite the mix-up," she told Mordin dryly, who shook his head wearily.

"Language," he said ruefully. "Doesn't always come out right."

"Still won't use a translator, though, I bet," Padok said, brushing a bit of green pond vegetation off Mordin's shoulder, and Mordin shook his head.

"Nope," he said smoothly.

"All right, well." Padok grinned and elbowed Mordin. "I hate to simply pull you out of a pond and run, but I've got to get going. Nice catching up with you, though."

"Yes," Mordin said absently. "Thank you."

"For what?"

"Idea about Collectors."

"Oh." Padok shrugged. "If it helps you, I'm glad. Good luck!" With that, he bid farewell and walked off, whistling.

"He's interesting," Shepard noted.

"Not always this friendly," Mordin chuckled, plucking a bit more vegetation from his sleeve. "Did not expect to fall in."

"Yeah, me neither. Come on, let's get you back to the Normandy so you can get some dry clothes."

"Wait," Mordin told her, and quickly downloaded their chess game to his omnitool. "Very well. Lead the way."

Author's Notes: Padok Wiks is a supremely interesting character and I WILL fight you on that. I'm still somewhat upset you can only interact with him if Mordin dies. (Also, yes, Padok Wiks has canonically punched Mordin in the face. That's in the game if you ask Padok about Mordin at some point.)

A small Covus glossary here:

pem - queen
van - king
rohk - knight
mnuy - check (when referring to chess)
kal - five
miel - six
an - one
sehk - yes
sao - no
bemaha - is that you

Everything else should be translated in the story.

Also, please forgive me, I am not a biologist and I am trying to write about biology! Tetrodotoxin does exist, and it does use sodium channel blocking to work, but that's pretty much where my knowledge stops.

Finally, that little "eff you" gesture at the end was partly inspired by the Indian/Pakistani gesture of flicking your thumbnail off your teeth. The American Sign Language sign for "thank you" is where you put your fingertips on your chin and gesture outwards and down. Is it possible to mix the two up? Yes. How do I know that? I'll give you three guesses...