Kai entered the abandoned building and climbed the stairs to his flop in the loft. "It's me," he called out. There was a grunt in response. Kai finished the climb and found Tenzin hobbling around the room. Kai set down the bag of food and took the man by the arm. "The doc said you should stay off your feet for the next few days."

"I can't stay idle that long," Tenzin grumbled but allowed Kai to guide him back to the mattress. He sat propped against the wall, scowling at a random spot on the floor.

"I brought dinner," Kai said, returning to the bag. He pulled out paper cartons, opened one, and looked inside. "It's only vegetables and rice, I'm afraid." He grabbed a pair of chopsticks from the bag as well and took Tenzin his meal.

"Well, I'm a vegetarian, so that sounds perfect. Thank you, once again." Tenzin inhaled deeply over the carton and took a bite. "It's splendid. You're too generous. I can pay you back. I have some money hidden away."

"Don't tell people things like that," Kai said around a mouthful of food. He gestured with his own chopsticks for emphasis. "You never know when you're dealing with someone who will take advantage of you."

Tenzin sighed. "Not long ago, I would have said you're too young to be so cynical."

"What would you say now?"

"That I'm sorry you learned that particular truth so early." Tenzin poked at his food. "I still wish you would let me repay you."

"Don't worry about it. I live cheap." He waved his hand at the loft.

"This food wasn't free. Nor, I suspect, was the man you had in to check my injuries."

The food had actually been liberated from the back of a delivery bike, although Kai suspected his guest didn't want to know that. As for the doc, well, that had cost a favor, but still... "There's been people who helped me out in the past. People I can't repay now. Let's just say I'm paying off some of those debts with you."

Tenzin nodded. "Paying forward instead of back. A noble principle with a long tradition. Very well, I won't insist. Instead I shall look for opportunities to follow your example."

Kai squirmed at Tenzin's praise. "You do know how I make my living, right?"

Tenzin looked sad. "Crime exists because all society is out of balance. I'm not saying I condone what you do. But it's a symptom, not the disease itself."

"I'm pretty sure a lot of criminals are just out for everything they can get," Kai said.

"A trait they share with many 'respectable' citizens."

Kai didn't have an answer to that. The two continued their meal in silence.

Korra didn't know what to expect from a public lecture at the university, but she could see a lot more people in the lobby of the physics building than she had expected. There was a young man stationed in front of one of the doors. She watched him hand a couple of people tickets and let them inside. Korra approached him. "Is this normal? I was expecting something a bit quieter." She gestured through the glass doors at the crowd.

"Normal? Not a bit of it. A whole bunch of people who couldn't care less yesterday are hoping Professor Beifong has something to say about last night's events."

"Last night? Oh. Right." So much had happened to her since then that Korra had forgotten that the latest Spirit attack had been just the night before.

"Are you in the program?" he asked her.

"Program? Oh." She shook her head. "I'm not a student. I met the professor socially, and we talked about his research. He suggested I might find his lecture interesting."

"Good enough," the young man said, ripping off a ticket and handing it to her. "We're making the reporters sit in the back. Show one of the other students this and they'll let you sit closer."

Korra thanked him and entered the building. Looking around the lobby, she guessed that most of the crowd was the reporters the student had mentioned. Most of them looked a little old to be students and a few were carrying cameras. She didn't see Opal Beifong in their midst. Of course she could ask her brother questions any time and also had an exclusive ringside seat to Baatar's upcoming meeting with the Avatar. She probably didn't need to be here yet.

Two people about the same age as the student outside flanked a door at the side of the lobby. Korra walked up and showed them her ticket. "Is this where the lecture is being held?" She was assured that it was and was ushered through. The lecture hall was a modest affair, seating maybe fifty people tops on folding wooden seats. A couple dozen people were already seated or stood in the aisles conversing. Korra chose a spot in a mostly empty row near the front.

Over the next several minutes the hall continued to fill. Many of the people seemed to know each other, so she guessed they were students. There were also a few older ones that might be professors. Maybe Baatar's peers were taking his research more seriously now. Others in the audience kept to themselves, and Korra guessed they were fellow members of the general public. Shortly before the lecture was scheduled to begin, the reporters filed noisily in from the lobby and into the back rows. Baatar entered shortly thereafter from a separate door at the front of the hall. Flash bulbs erupted from the back of the room, prompting him to shield his eyes. The volume level in the room rose sharply as the reporters clamored for attention. Baatar held up his hands and gestured for silence. The reporters continued to call his name and shout out questions at him. At last he took a deep breath and bellowed "Quiet!"

Silence fell. "Thank you," Baatar said with only a hint of irony in his tone. "It's gratifying to see so many faces here. It's understandable that recent events should spark new interest in the Spirits, and the timing of my lecture must have seemed particularly fortuitous. I'm sure you all have many questions, but this is an academic event not a press conference. I will be giving my talk as originally planned." Korra joined in the smattering of applause that came from the students at the front of the hall at this announcement. "I hope it will be of interest to all of you," Baatar continued. "There will be time for questions at the end. And while I will prioritize questions directly related to my presentation, I'll also attempt to answer questions on more general matters. I'll warn you in advance that my answers will be highly speculative. Most of what I know of current events I have learned from the ladies and gentlemen of the press." He gestured at the back of the hall. "I do not guarantee that I have any newsworthy insights. Now then -"

"Professor Beifong!" Korra turned to look at the man in the back who had interrupted. "Your sister is a reporter for the Dragon-Sentinel. Do we have any assurance that we will be receiving the same information you are providing her?"

Baatar removed his spectacles and polished them with a handkerchief until the murmuring of the audience died down. He replaced his glasses and fixed the reporter with a stare before speaking. "I intend to answer all your questions frankly and to the best of my ability. The only possible advantage my sister has is that she knows me well enough to not annoy me accidentally. The flip side of that, of course, is that when she does annoy me, I know damn well it's on purpose." This last remark earned a chuckle from the audience. "Since you lack this advantage, in the interests of fairness I'm willing to assume you are annoying me by accident. I will still answer your questions after the lecture provided that right now you sit down and stop talking." There was another round of applause from the students, and the red-faced reporter sank into his seat.

"As I was about to say," Baatar said, "an objective and rigorous study of Spiritual phenomena faces many practical difficulties..."

"Should the shipping companies start burning offerings?" Korra rolled her eyes heavenward at the reporter's question. Up at the lectern, Baatar maintained greater composure. His warning that he wouldn't be able to shed much light on current events had been accurate so far, but Korra was hoping that it might be due to the poor quality of the questions. Many of the reporters from the less reputable papers were treating the occasion as an opportunity for satire. At least this guy seemed to be serious, and Baatar treated him as such.

"I don't think anyone can recommend corrective measures until we understand what is angering the Spirits. And while we've got ample historical records on traditional methods of pleasing or placating the Spirits, it's an open question as to whether the Spirits themselves gave any notice of those rituals." He shrugged. "I doubt it would do harm, but it may well be a waste of time." He glanced at his watch. "I'm afraid that's all the time we have, ladies and gentlemen. Thank you once again for coming. Have a pleasant night." He picked up his notes and exited the way he had come in, ignoring a last flurry of questions from the back of the room.

Korra consulted her own watch. Twenty minutes until she was expected to show up as the Avatar. Plenty of time to get into character. The crowd filed out of the hall, breaking into small knots in the lobby or out in front of the building. The reporters sounded disgruntled; the students, excited. Korra left the crowd behind, walking away from the physics hall and past the neighboring campus buildings. Glancing around to make sure she was unobserved, she slipped into an alley and summoned an airball to carry her to the rooftops. Conveniently, the nearest neighbor to the physics building was a couple stories higher. Korra pulled her mask and gloves from her jacket pocket and shed the outer layer of clothing that was concealing her costume. She concealed her street clothes and settled in to watch the roof of the neighboring building.

At the appointed time, a rooftop door on the physics building opened and Opal and Baatar walked onto the roof. She watched them long enough to be sure no one else would join them and made a wind assisted leap down to where they stood. Baatar stepped back with a strangled cry. Opal barely flinched, and as if this were an everyday occurrence, stepped forward smiling, hand outstretched. "Glad you could make it," she said, shaking Korra's hand.

"Thanks for arranging this meeting."

"My pleasure." Opal turned to her brother. "Baatar, this is the Avatar..."

Baatar, who had spent most of the lecture looking stern and slightly peeved now looked like a kid whose biggest nameday wish had just come true. "Do you know your documented powers violate all known conservation laws?" he blurted.

Opal sighed. "May I present my big brother, Professor Baatar Beifong Jr, who is usually not this big of a goof."

Korra shook hands with him. "Is that bad? The conservation thing?"

He shook his head. "It's amazing! It's exciting. It means there are new frontiers of science we haven't even dreamed of yet."

"That's not what we're here for tonight, though," Opal said.

"Of course. Pardon me. I'm just a little overwhelmed. Shall we go down to my office?"

At this hour the building was empty enough that the brief walk from the service stairs to Baatar's office posed no risk of discovery. Opal shut the door behind them so their privacy was guaranteed. The office was considerably less tidy than when Korra had visited it unmasked. Books and journals had been pulled off the shelves and now lay stacked precariously with bookmarks sprouting from them like mushrooms after the rain. The desk was covered with scribbled sheets of notepaper.

"Pardon the mess," Baatar said, stepping past her. "I got the files you gave my sister, and it took me most of the day to pull some preliminary results together. This is the first item I think you might be interested in." He gestured to the map of Spiritual sites he had shown Korra previously. As he repeated the explanation of his research she studied it again. He'd updated it since she saw it last, and his explanation quickly moved into this new territory. "These two shrines are located fairly close to the first two incidents and are associated with particularly powerful Spirits." He pointed at the locations which were now circled in red ink. Next he gestured to an island in Yue Bay not far from the main shipping route that had a big question mark over it. "Last night's attack I'm less certain about, but many of the local islands had centers of worship. My research hasn't covered that ground well, particularly on the islands with little or no permanent human population. I think, tentatively, that the Spirit you confronted last night might have a shrine here. Having such clear photographs will help corroborate with written accounts." He nodded at Opal.

Korra nodded. "Any possibility that we can use this to predict potential future targets?"

Baatar went to his desk and picked up a street map. "I marked this up for you. Not all of the shrines I researched are linked to Spirits that are reputed to have a strong physical presence when they manifest. I made special note of the ones that do."

"How difficult would it be for someone else to reproduce this research?"

He spread his hands. "Not terribly difficult, although certainly time consuming. Most of my sources are available in modern reprintings. Of course I was interested in identifying everything I could. Whoever is behind this has a more — well, I hate to say practical, but I can't think of a better word — they have a more practical focus and could concentrate on Spirits with a more active presence in their folklore."

"So you sound fairly convinced that we're right in our guess that the Spirits are being deliberately goaded using the devices we keep finding."

"Well motive isn't my department, but I have no doubt that you're right about what the machines are doing. I even found some corroborating evidence linking spiritual sensitivity to people experiencing the adverse effects." He pulled a sheet of paper out of the chaos on his desk. "I've got a side project investigating claims of psychic abilities. Precognition, that sort of thing. I made some follow-up inquiries with the subjects in my study, and there is a strong correlation between the individuals whose claims are credible and the ones who suffered headaches or other symptoms during the attacks. Not good enough statistics to publish, but compelling nonetheless."

Korra nodded. "Well that's something. Any ideas how we can counteract what the machines do?"

Baatar grimaced. "I'm still working on that. It depends on how the Spirits experience these 'M-rays'."

"Good name, by the way," Opal added.

Korra laughed. "Thanks. There's a minority opinion that they should be called 'S-rays' for Spirit."

Baatar and Opal exchanged a look. "No," they said together.

"Anyway," Baatar continued, "There are two things that the Spirits are traditionally hostile to. The first is damage to nature."

"The M-rays can't really be worse than the everyday pollution of the city, can they?"

"Unlikely, but I wonder if the people behind the attack have figured out how to mimic the metaphysical imprint of something truly damaging."

"Interesting. What about the second thing?"

"Negative emotions," Baatar said. "Specifically hostile ones. It's not clear whether the Spirits interpret them as an attack or if they arouse a protective reaction."

"You mean that maybe the Spirits aren't hurt at all?" Opal broke in. "Maybe they know these device hurt people and go after them for that reason?"

"Possibly," he answered.

"The one I tried opening a dialog with wasn't interested, not that that means much," Korra said absently. She had a queasy feeling in the pit of her stomach. "So we've been wondering about the source of their signal. What if you had a person with a natural affinity with the Spirits, and this person also had a strong sense of grievance and possible anger management issues? Could you get a 'negative emotions' signal from that person and broadcast it with these devices?"

"You have someone specific in mind, don't you?" Opal said.

"I've got my suspicions," Korra answered.

"It's plausible," Baatar admitted. "I don't immediately know how from what we have on hand, but in principle a receiver is just a broadcaster in reverse. If you like, I can work on that hypothesis."

She nodded. "Please."

"What I want to know," Opal said, "is where they got these things in the first place. I mean, they didn't come to you to knock together their evil Spirit radio."

Baatar's open manner had dispelled most of Korra's lingering doubts about him, but she still watched his reaction carefully. If he had a guilty secret, he was a frighteningly good actor. "I'm not the first person to bring science to the study of the Spirits," he said. "You've heard of the inventor Lonaki?"

"Not a bit," Opal said cheerfully. Korra felt relieved that she wasn't the only one.

"She designed the generators that light this entire city," Baatar said in a slightly miffed tone, "so she was kind of a big deal. Anyway, late in her life she devoted her studies to more esoteric pursuits, including trying to invent a device to communicate with the Spirits. People thought she was crazy. I've read her papers, though, and I was never so sure. We might be seeing her work vindicated."

"The bad guys have a secret Lonaki blueprint?"

"Not necessarily. I'm just saying they might have built on her work. Or made discoveries all on their own. There's no limit to human ingenuity."

"For better or for worse," Opal said. Baatar conceded the point with a nod and a wave of his hand.

"Well, your work here counts in the 'better' column, I think," Korra said. "This is a big help, and I'm grateful."

"Being in on this work is its own reward," he said. "I just wish the circumstances were more pleasant."

Baatar had still had work he wanted to do in his office, so Opal escorted Korra back to the roof on her own. "Just one thing before you go," she said.

Korra looked at her curiously. "Go on."

"The deal we have. About you giving me the inside scoop in return for my help? Don't worry about it."

"Don't —?"

"I mean, I'll print anything you want to give me. Gratefully. I'm just not making the story my price. If there's anything you need, just ask." She turned away from Korra and looked out over the edge of the roof. "Bolin and me, when we were out trying to get pictures last night, we pulled a sailor out of the water. He'd been knocked overboard. I checked with the hospital. They don't know if he'll wake up, and if he does he probably won't walk again. Spinal injuries. The people who did this, they don't care. It's all just part of their scheme. I can't stand by if there's something I can do to stop people like that." She laughed bitterly. "I probably should have figured all this out the first time we worked together. More people died in those fires than have in the Spirit attacks. I guess I needed something to make it personal. You don't. I admire that."

Korra laid a hand on Opal's shoulder. "Don't beat yourself up. You're a good person. And when you write the truth for your paper, you're doing good work." Opal turned and gave her a half smile. "And thank you. For your offer and for all you've done already. Go home and get some rest."

Opal laughed. "Is that what you're going to do now?"

Korra thought about Asami waiting for her back at the Meditation Center. They would have a lot to talk about concerning the case. And hopefully, they could squeeze in some personal time. "Eventually."

It was late by the time Mako was able to get hold of Shin. "Sorry about that. I was out with my girl," Shin said as he let Mako into his garage.

"No trouble. Sorry to bother you at this hour."

Shin grinned. "No rest for the wicked, right? What have you got for me?"

Mako handed Shin the folder of police sketches. "I managed to get some extra copies of these at work. The Ghost wants them distributed to the network."

Shin opened the folder and looked at the top sheet. He whistled. "Hey, this is pretty good. How did you get hold of it?"

Mako frowned, puzzled. "One of the sketch artists on the force drew it."

"I didn't know the cops knew anything about it." Shin rapped the picture with his knuckles. "Where did you find a witness who wasn't too scared to come forward?"

"Scared to — Shady, who do you think this is a picture of?"

Shin looked at him, brow furrowed. "I don't 'think.' I know. This is the geezer those Dai Li bastards were looking for."

Mako stared at him. "This is our best suspect for who's the Voice of the Spirits."

Shin looked back down at the sketches in his hands. "Well, crap," he said.