Back at his desk in the tourist office, Ianto stared at his screen for the better part of an hour without accomplishing anything. Without the distraction of challenging work to focus on, his thoughts kept returning to Jack's office, replaying every moment of the concern and tenderness Jack had shown—and that was the one path Ianto couldn't afford to let his mind wander down.

At last he gave up the pretense of work and bent all his faculties to consider his present situation. He certainly felt that he was on a better footing with Jack now (aside from that moment of weakness in Jack's office, of course; he'd have to watch himself), but the matter of SoulMatch, his prescription pills, and above all, his missing signum still weighed heavily on him. He couldn't allow things things to continue as they were. He needed to take action—but what?

Should he confide fully in Jack about what Owen had found in the pills? Would doing so endanger the information about his signum? Jack had been anxious for Ianto's wellbeing, and revealing what Owen had learned about the pills might push him to act on that fear. If SoulMatch thought Ianto was responsible for an investigation, they might cut him off entirely, or destroy his file, and he could risk losing his signum forever.

But if he said nothing, SoulMatch might continue with their operation—whatever it was—and continue to stall him, or worse yet, dose him with something more powerful than the triple oxytocin he'd been given over the past few weeks. Not to mention whatever chemicals Owen hadn't been able to identify.

Ianto groaned and dropped his forehead to the desk. No matter what path he chose, there would still be the underlying fear that his decision might have been affected by the residual drugs in his system. How could he confront SoulMatch when he was still effectively under their spell?

Well, he wasn't likely to learn anything sitting here. Perhaps Owen had discovered something new in his testing. It had been a slow week; even the few tourists who had stumbled across the information office hadn't wanted anything more than a souvenir magnet, and those were available at the opera house gift shop and a dozen other retailers within a five-minute walk. Besides, in his current mental state it wasn't as though he could accomplishing anything of value up here. Ianto locked the tourist office and took the lift to the main level of the Hub.

The moment the cog door rolled back, his eyes began to water. Gwen was nowhere to be seen, and Ianto envied Toshiko her containment cube and protective filtration gear as he coughed and scrubbed his burning eyes. Jack's office doors were closed, and peering through the glass, Ianto could see that the hatch door that led to his bunker was sealed tight. None of the environmental alarms was sounding, though; evidently whatever the noxious odor was, it wasn't toxic.

A short jog to the medical bay revealed the source of the acrid fumes. Owen was finishing up another alien dissection, his own body shielded by a hazmat suit. This corpse was grey and putrid, and a sickly green ooze emanated from the Y-shaped incision Owen had made in its torso. As Ianto squinted over the railing, Owen tied off the last stitches to close up the corpse. Ianto debated fleeing to someplace with fresh air and coming back later, but he really didn't want to make two trips through the searing cloud.

"Owen," he gasped through his handkerchief, "got a question, when you're free." He succumbed to a fit of coughing. "Should I be breathing this?" he choked out.

Owen grunted something incomprehensible through the suit's respirator. When it was clear Ianto didn't understand, he followed it with a series of hand gestures that Ianto interpreted as instruction to move to the upper level. He did so without delay, climbing nearly all the way to Myfanwy's aerie before the burning subsided enough for him to breathe without the cloth over his face.

Several minutes later the clang of a slamming freezer door echoed through the open space of the Hub, eerily silent without most of its personnel or its resident pteranodon, who had evidently fled the smell along with the others. Soon Owen joined him on the elevated catwalk, free of the suit but red in the face from holding his breath all the way up the stairs. He slumped over the rail beside Ianto and coughed.

"I may never be the same," he panted. "That smell is burned into my sinuses. They're like alien skunks, those Mephitians." He dropped down onto the walkway's metal grating, cross-legged. "What'd you want to talk about?"

"Just a moment." Ianto crossed to a control panel and switched on a set of rarely-used ventilating fans. He normally left them inactive, as the vibration seemed to disturb Myfanwy, but under the circumstances it seemed prudent to pump out as much air as possible. "That should help. Where are the others?"

"If they're smart, someplace with oxygen. Once the thing's scent pouch blew, it was like a tear gas strike. I saw Gwen running for the vaults while I was trying to get the hazmat suit on. Tosh is probably still in her containment cube, enjoying purified air."

That meant they were all out of hearing, at least. Ianto leaned against the rail across from Owen. "I have a question about the pills. You said they were dosing me with three times the oxytocin, yes?"

Owen nodded. "From the capsule I tested, it appears so."

"What would be the purpose of that, then? Oxytocin is a natural hormone. What advantage could they achieve by overdosing me?"

Owen shrugged. "At best, it might make you more pliable. More trusting. That's a long shot; not everyone reacts to it the same way. But maybe combined with some of those other unknown compounds, it's more effective? I don't know, maybe they wanted to subtly influence you in some way. Make you trust them, or stay in their program. Something like that."

"They were very insistent that I continue with the research study." He recalled a conversation with Dr. Peters, and clicked his fingers. "And when I suggested discontinuing the pills, they actually raised my dosage. I wonder if that was the cause?"

Owen nodded thoughtfully. "Subject gets suspicious, they dope him to make him more trusting so he doesn't leave the program. If there's any question, nothing shows in his bloodwork because the oxytocin is supposed to be there, and nobody's testing for the other compounds. It's a theory. Not medically reliable, but then we don't know what else they're using. There could be some other drug administered at the appointments, too." Owen stared meditatively at the water tower, receding beneath them toward the Hub's lower levels. "Tell me about these study appointments. What do they do there? What information do you give them?"

Briefly Ianto outlined the usual routine, describing the questions, scans, and blood draws. Owen listened attentively, then shook his head. "I don't know. Whatever their game is, it has to be a long one. Think the air's clear down there yet?"

Ianto glanced at the ventilator fans whirring overhead. "Better now. Why?"

"Let's go down to the lab; I want to take some blood."

Ianto had seen enough needles in the last two months to last him the decade. He rubbed his arm reflexively. "Is that really necessary?"

"It is if I'm going to compare your current blood chemistry to what's on record in your file. I want to see if they've been doing anything else to you, besides making you more cooperative. And I want to take another look at those unknown proteins, see if I can find anything complimentary in your system that suggests their function." He flashed a grin that did not reassure Ianto. "I'm gonna pull out the big guns on this one. Use the carboxomide scanners."

Ianto raised an eyebrow. "I have no idea what that is, but it sounds impressive."

"Alien tech. Advanced neutron path graphing, so Jack says. I haven't gotten to test drive it yet."

Ianto frowned. "But what do neutron paths have to do with—"

"Oh, c'mon, it'll be fun." Owen stood and urged him toward the medical bay. "We've got a mystery to solve. Might as well take the opportunity to play with the new toys."

Despite Owen's assertions, Ianto found nothing fun about having several vials of blood drawn from his arm. Even before he had rolled down his sleeve and secured his cuff, Owen was cheerfully adding samples of blood and capsule powder to the glass chambers of the carboxomide scanner, which resembled nothing so much as a cluster of neon light tubing growing out of an old adding machine. For a few minutes Ianto watched him adjust dials and punch buttons, until the machine ejected a slim sheet of transparent film from a slot on the side. The film was dotted with dozens of tiny triangular holes.

"Fast results," Owen said approvingly. "Now I just have to remember how to change the settings on this universal punchcard reader Tosh built…" He fiddled with a box connected to his computer, then shoved a stapled packet of coffee-stained paper at Ianto. "Here, check that list and tell me which protocol Telendrien tech uses."

Ianto skimmed the columns of tiny type in the reference guide. "The Telendrien interface code is 0435-V." Ianto looked over Owen's shoulder as he input the code and slid the card into the slot. "So tell me what this thing does, exactly?"

"Among other things, it's an advanced imaging system. Should give us a better picture of what we're looking at—in three dimensions, down to the molecular level. There!" Owen straightened and flipped a switch. The machine whirred and vibrated. "This may take a few minutes, if you want to go make coffee or something."

Ianto couldn't imagine that the lingering odor in the Hub wouldn't adversely affect the flavor of coffee, and he had no desire to waste good beans. Restless, he left Owen alone in the medical bay and relocated to the doctor's workstation. He took care of a few administrative tasks, checked his email, and finally began researching SoulMatch. Know your enemy, he reminded himself. Or your health care provider. Or… whatever.

He was reading an interview with one of the company's founders when Toshiko's voice erupted behind him. "Eureka!"

Ianto turned to see Toshiko emerging from her plastic cocoon, where she'd been sequestered with her analysis equipment for the past few hours. "Been bathing?" he quipped.

Toshiko ignored him. "I've got it! Finally!" After a few seconds her broad grin faltered, and she sniffed the air. "Ugh! Has someone been slicing onions?"

Ianto gestured toward the medical bay. "Owen's necropsy subject got fresh."

"Smells the opposite, to be honest." Toshiko squeezed her eyes shut. "Phew, my eyes are burning. I think I was better off in containment."

The door to Jack's office swung open and the captain emerged, waving at the air before him. "You should have been here an hour ago, when the damn thing blew." He glanced up toward the ceiling; the hum of the fans was just audible. "Oh, good call with the exhaust fans, Ianto. Bet we've cleared Mermaid Quay with this, though."

"Disrupted the lunches of a few tourists, but I've already reported it as a sewer gas incident." Ianto spun the chair back to face Owen's computer. "I even planted complaints on social media. Hashtag 'offalbasin' is now trending on Twitter."

Jack chuckled and turned to Toshiko. "What've you got, Tosh? I heard a 'eureka.'"

Toshiko held up a tablet. "Oh, right. The pollen! I finished the preliminary analysis. It's definitely organic—entirely organic, in fact. I've finally isolated the protein that comprises most of it—that's what the 'eureka' was. The structure is… weird."

Jack frowned. "Weird, as in dangerous?"

"Not on immediate contact, according to my simulations. It appears to be relatively inert. But we still don't know for certain what it is or what it's for. I'm running a comprehensive database search now." Toshiko set down the tablet and rubbed her face, which bore deep imprints from the elastic of the respirator she'd been wearing. "Hopefully that will turn up a match, so we can figure out exactly what we're dealing with."

"You said it's organic. Some kind of seeds, maybe? Terraforming?"

Toshiko shook her head. "Not nearly that developed. There are a lot of basic building blocks present—amino acids, a few complex proteins—but no tissue. It's almost like a powder mix for primordial soup."

Jack came closer and picked up the tablet, scrolling through her results. "Could it be a disease agent, you think?"

"Maybe, but not any kind of virus or bacterium I've seen. You might get Owen's opinion." She reached over and selected another readout. "Look at this. I've isolated only a few complete cell structures in the sample I collected. I'm still waiting on the computer analysis, but to my eye the thing it most closely resembles structurally is nervous tissue. Here's the 3D render I've constructed. See these nodes? But of course that doesn't make sense for something that would be dispersed through the air."

"Hang on." Owen, who had climbed halfway up the stairs to listen, popped his head over the edge. "Tosh, have you got that diagram handy?"

Toshiko retrieved the tablet and walked it over to him. Owen vanished down the stairs with it, and a moment later, shouted, "Ianto! You mind coming down here?"

Jack gave Ianto a curious look as he hurried down the stairs, and he and Toshiko followed close on his heels. Owen glanced up at Jack, then at Ianto. "You okay with them knowing about…?"

Ianto repressed a sigh. "Nothing stays secret for long here, anyway. Go ahead."

Owen nodded, then pointed to the screen, which displayed a three-dimensional model of some kind of particle. "Tosh, does this look familiar?"

Toshiko's dark eyes flicked over the readout. "Of course. It's the proteins I isolated from the sample."

"Except it isn't." Owen toggled to another screen. "These are your proteins. This—" He split the display between the two images, side-by-side. "—is a model of a protein I isolated from another source, this morning. The carboxomide scanner just finished constructing this image."

Toshiko stepped closer, looking from one model to another. "But they're identical!"

"Quite a timely coincidence," Jack observed. "Where'd you find it?"

"In a prescription pill I analyzed. Whatever it is, some pharmaceutical company is putting it in their capsules. And no, it doesn't belong there."

Jack glanced between Toshiko and Owen. "Okay," he said slowly. "What do pharma companies and alien drones have in common?"

"That," Owen picked up Ianto's prescription bottle and handed it to Jack, "is a question I suggest we ask SoulMatch."