We’re thrilled to share an excerpt from The Potency of Ungovernable Impulses, the third book in Malka Older’s Investigations of Mossa and Pleita, out from Tor Books on June 10th.
When a former classmate begs Pleiti for help on behalf of her cousin—who’s up for a prestigious academic position at a rival Jovian university but has been accused of plagiarism on the eve of her defense—Pleiti agrees to investigate the matter.
Even if she has to do it without Mossa, her partner in more ways than one. Even if she’s still reeling from Mossa’s sudden isolation and bewildering rejection.
Yet what appears to be a case of an attempted reputational smearing devolves into something decidedly more dangerous—and possibly deadly.
Prologue
There were not so many places to lurk in the scholars’ residence on Thanma Street. Certainly, to while away some time while waiting out a storm or for a visitor, the place was replete with comfortable options: the library; the game room; the common room, if one could gain access. But furtively keeping an eye on a scholar’s accommodations was more difficult, the narrow landings offering little but those austerely closed doors. In principle, Mossa approved of the protection from outside eyes; in practice, she had found herself unable to knock and unwilling to return home and extremely averse to being the object of pitying or curious glances.
Fortunately (or un-; perhaps a complete lack of cover would have goaded her into a more salubrious decision?) there was an access panel that allowed for repairs to the dumbwaiter shaft from the landing. There was always something in people’s lives that they wanted to pretend was magic and effortless; hiding those mechanics usually offered hiding places for less desired intrusions as well. Mossa crouched there, the panel door pulled almost shut, and argued with herself until she heard footsteps and pressed her eye to the opening.
A person with an amiable gait toddled up to the door in question. Even expecting it, the knock made Mossa flinch; she closed her eyes before the door opened. She had already recognized Lessenan, a scholar with rooms on the next floor up, and was unsurprised at her opening sally.
“Hullo, Pleiti! What do you think about a concert tonight?”
Lessenan had a conveniently loud baseline tone; the reply was more of an uncertain murmur. Mossa opened her eyes again, but Lessenan also had a large and inconveniently located back.
“It’s the Classical orchestra. They’re doing Maalouf in the first section and the Indigo Girls in the second. Come along, do, it’s been ages since we’ve been to a show.”
Go ahead, get out, enjoy yourself, Mossa thought, and at the same time, less coherently, hoped that wouldn’t happen.
“Well,” came the reply, a little clearer this time (that would be Pleiti remembering that Lessenan was hard of hearing). “Well, no, I think I’ll stay in tonight.”
“Waiting for someone?” Lessenan asked, all twinkly.
“No… no. Just, you know… busy. And the fog is terrible. Maybe another night?”
“I’ll hold you to that!” Lessenan was cheerful, pleasant, in a committed ace relationship, and not inclined to women. Mossa knew she needn’t feel the faintest twinge of jealousy, but in her current state it was impossible for her to imagine Pleiti wanting her, or benefitting from her association in any way, and so even Lessenan seemed like a rival. No, not a rival even: simply a better option.
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The Potency of Ungovernable Impulses
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Mossa leaned her forehead against the too-close wall. She should leap from this ridiculous shelf she was huddled on and go to the woman who was obviously waiting for her. Or if she couldn’t, really, really couldn’t, she should send Pleiti some excuse so she would know she was free to attend the theater with whomever she liked.
Instead Mossa stayed in the access cubbyhole for some indeterminate amount of time, her temple against the cool wall of it. She should go in, she should go in, she should free Pleiti entirely or she should go in and love her.
It took so much effort to push open the panel, unfold her legs, and stand up in some posture approximating upright. She looked at the door, imagined Pleiti on the other side, comfortable and happy by the fire.
She should go in.
But instead she turned for the stairs.
Chapter 1
A storm was writhing over Valdegeld, its tendrils churning Giant’s ever-present fog and pressing sleet and freezing rain through the atmoshield and onto the august buildings of Valdegeld University and auxiliaries, including my—less august, but evocative and comfortable—lodgings.
I had canceled my last tutorial of the day, knowing the student needed more time to gnaw on their thesis in any case, and had long since been ensconced in my rooms with a blazing fire, a pot of tea, and a plate of scones up from the kitchens. I had spent a few dutiful hours with my work, but as the evening wore on I had decided it was well past time for leisure and switched to a Modern novel instead, a tale of early settlement derring-do and romance, with a railcar heist and a space shuttle rescue that fit the mood of the evening.
I had been rather hoping that Mossa would come for a visit. She had been somewhat, amorphously, absent of late; uncommunicative, or offering excuses that seemed reasonable until considered in bulk. I had been trying for some time not to feel worried about the situation—surely, after all we had been through together, surely if something was wrong she would tell me?—and I did not want to miss any opportunity for intimacy with her, so when a friend suggested going for a concert that night I refused, just in case. However, if she were to join me that evening I would have thought she would arrange to arrive before the worst of the storm, and my hopes had dimmed considerably when a knock on my door raised them again.
I opened it with Mossa’s name on my lips, only to see instead a narrow wedge of a woman, her coif showing some of the effects of the storm, a dripping raincoat and atmoscarf over her arm and a determined smile on her face. “Hullo, Pleiti,” she said, a little hesitantly. “How are pubs?”
Her face was uncertainly familiar, but I couldn’t immediately identify it, not when I was expecting to see Mossa’s instead. Before I could make too great a fool of myself, Nakalo the porter leaned around her shoulder. “Sorry for bringing her up directly, but as a scholar and she said she knows you from student days…”
Bless him, the name popped right into my head. “Petanj! It’s been so long. Er, would you like to come in?”
She hesitated. “Not if it’s not a good time for you. Or, well, we could meet somewhere else, it’s just, there’s a small matter…”
I tend to be somewhat jealous of my rooms, but I had become slightly more sociable of late, and in any case the unheralded appearance of an acquaintance on such a night had aroused my curiosity. “Not at all, not at all.” I mouthed a thank you to Nakalo behind her back as I closed the door and ushered her to the fireplace, wondering the while. I knew Petanj, as Nakalo had intimated, from when I had been at Valdegeld the first time, as a student; like me, she had since earned a place as a scholar—even before I had, if I recalled right—but she was in the Modern faculty, less prestigious than my Classical appointment. As the faculties didn’t mix very much, and we hadn’t been especially close as students, I didn’t see her often; indeed, I wasn’t sure I’d met her more than once since returning to Valdegeld. For her to appear in my rooms, therefore, particularly on such a tempestuous night, suggested some significant motivation for the visit.
“Thank you,” she said, letting me take her raincoat to hang it up. “I know it’s unconscionable, my coming here without any warning, but I just don’t know where else to turn.”
“Oh?” I couldn’t imagine in what arena I could be a place for her to turn, but my heart was beating faster nonetheless. “Please tell me what I can do for you. But first—some tea? Something to warm you? It’s horrid out.”
“It is. Tea would be lovely, thank you.” There was a brief silence while I put in the order, and it stretched after I had seated myself. At last Petanj swallowed and spoke. “Forgive me again for the intrusion. I… well, I have heard that you had a, er, a connexion of some kind with the Investigators…?”
I answered as carelessly as I could. “Oh, you mean Mossa. She’s not here tonight, but I’m sure… Didn’t you know her at school?”
“Not—not very well.” I wondered if the tinge of embarrassment was from vaguely disliking Mossa (as many people did) or from liking her too much (as some people surely did as well). “Is that… well, what I mean to say is, perhaps you can help.”
I hoped my face was bland. “If you’re looking for an Investigator—” I hesitated. It would be rude to tell her to go directly to their bureau; unbearable to think that if I sent her to Mossa’s place Petanj might see her before I would; presumptuous to the point of risible to suggest I could manage whatever it was instead.
“No! No. I was hoping for you, in fact.” I felt my eyebrows rise in disbelief. “That is…” She twisted her hands. “When I heard about the things you’ve done recently, you and Mossa, well—I thought perhaps you could help me. An Investigator… well, they might help or they might make it worse, if you understand.”
The service bell dinged, and I stood to get the tea, considering what she meant. “It’s a… a reputational matter?”
“Exactly,” Petanj agreed hurriedly. “Exactly that.”
Everything seemed much easier suddenly. “Not to worry. Mossa is entirely discreet—” I hesitated again. She was, but it also seemed very unlikely that she’d be even distantly piqued by the sorts of petty academic bickering that I imagined we were talking about (especially, my undermind whispered, in her current range of moods). “And she’s much more understanding of, er, academic nuance than most. But she is quite busy, of course…”
“Yes, I’m sure. And her responsibility will be to the Investigators’ Bureau, naturally, and I’m not sure that those official channels would be the wisest approach for this. They might not understand the, the seriousness of it.”
“Precisely,” I agreed, pleased to have found a potential excuse that wasn’t solely reliant on Mossa’s personal inclination. “If she’s wil—that is, if she has availability to take on an additional case, I can tell her what we’ve discussed.”
“Then you’ll listen?” Petanj leaned forward with such a melodramatic mien that I instantly felt guilty.
“I may not be able to help at all, mind. But yes, I’ll listen.”
“That alone would be an enormous relief.” Petanj took a fortifying sip of tea, then leaned back and began her tale. “I am not here for myself really, but for my cousin, Villette.”
“I remember you were close,” I commented, pouring.
“Yes, more sisters than cousins. We grew up on a small platform and—in short. I don’t know if you heard, but a few years ago Villette received an appointment in the Modern faculty at Stortellen.” I clicked my fingertips in polite admiration. Our Classical faculty was far more renowned, but in Modern studies Stortellen was nearly as well-thought-of as Valdegeld. “She was quite pleased, and I was naturally very proud, although we did hope at some point in the future we might find appointments in closer proximity.” Stortellen was about as far away as it was possible to get on the network of geo-synchronized rings and platforms that formed humanity’s habitat on Giant; the initial logic, of course, being to provide universities within reasonable distance of all platforms.
But it was more than two days of travel between Valdegeld and Stortellen, and that if the connections were good; reasonable that these sisterly cousins might have wished to be closer together. Reasonable even that the distance might engender some worry. I wondered if Villette had disappeared, or if Petanj thought she might have; that seemed like the sort of problem she might have sought Mossa and myself out for, given our recent adventures.
Petanj was silent for a time, her lips pressed neatly together. I leaned forward to refresh her tea, though I didn’t have quite enough in the pot to fill her cup all the way, and that seemed to rouse her. She lifted her cup, raised her eyes to mine. “She has come up for the possibility of a donship.”
“Enhorabuena,” I murmured, with surprise—at her age, it was quite an accolade—but Petanj had barely paused.
“It seemed likely, I thought. Then, last week, she was accused of falsifying data.”
My stomach dropped. “In truth?” Mossa did not have much patience for meaningless expostulations, and I quickly gathered myself to say something useful. “Who accused her?”
“It was anonymous, which naturally created much skepticism, and perhaps it will come to nothing, but…”
“But of course they had to look into it.” I still felt sick, imagining it. And I could see why she wouldn’t want to go to the Investigators without a conduit; even those accustomed to working in university platforms would not fully understand the vital threat of your research being undermined; might not understand how devastating a careless investigation could be. All it would take was a thoughtless interview question—Have you ever seen any suggestions of plagiarism by this person?—to the wrong person, and an academic career could slip down the rungs of prestigious positions, or all too easily disappear altogether. I grasped for some cheer. “Well, and if the university is looking into it”—rather than dismissing her or quietly letting the donship possibility evaporate—“that is a hopeful sign, surely?”
“Yes. Yes, I do hope so. Villette has assured me there’s no need to worry, she says it is certain that the evaluation will vindicate her. Of course, she would say that—because she herself knows she is innocent of any wrongdoing, you understand, but also because she’s awfully trusting, my cousin.” Petanj frunced slightly in disapproval. “She attributes to everyone a general good faith comparable to her own, but even more than that she has a confidence which I cannot at all share that institutions— well, the university in particular, but also the committees; the student guild; the Investigators, for that matter; et cetera, et cetera—are all doing their best towards their stated purpose.”
This, too, started an uneasy resonance within me. I had been badly quaked by my university’s role in the cases I had helped Mossa investigate, the more so because I had not realized I was so trusting of them.
“It had occurred to me to request a separate investigation of the accusations, in case the university efforts proved, let us say, insufficient. In truth, I have for some time wanted a confidant for these worries,” Petanj admitted. “But I had not made up my mind to take such a step—I know Villette will call it unnecessary interference, although she might not mind so much if it’s you, Pleiti—and if that were all I probably would not be here.” She paused long enough that I itched to prompt her; but, again thinking of Mossa, I refrained. At last Petanj spoke again, her eyes fixed on my rug as though she were thinking carefully about each word. “Yesterday I received this letter.”
I held out my hand almost without thinking (it was what Mossa would have done) and perused the laminate she handed me. “Troubling,” I remarked, starting my first reread. The brief mentioned anonymous missives and malicious chisme, and urged Petanj to arrive as soon as possible to urge caution on your cousin as only you can; I was unsure how caution would help with these (presumably) foundless accusations. Did she fear some physical harm? That did seem suggested by the reference to ambiguous alarums, but perhaps that just meant the chisme. “But sadly lacking in specifics.” There was something about the tone of the note—for it was little more than that—that worried me, as though the author intended some double meaning, or perhaps simple insincerity, but I couldn’t be certain. It could even, I thought, be intended as either a threat or a cubreculo by the very author of Villette’s distress. I peered at the signature: one Wojo K’tuvi, Modernist scholar. The name sounded distantly in my memory—perhaps I had seen it in a citation list in one of my few ventures into reading Modernist scholarship? Rather telling to sign with one’s title, I always thought.
“Wojo is… particular, of course,” Petanj said with a mueca, perhaps noticing my attention to the designation. “But I have gotten to know her better in my visits, and I do not think she would exaggerate such things. This has convinced me that there is a thorough-going effort to discredit my cousin; that even if the”—she lowered her voice, perhaps unconsciously— “plagiarism accusations are refuted, the campaign will likely continue—possibly even escalate.”
I nodded slowly. I could imagine it all too distinctly: struggling with the obscure and onerous university bureaucracy, far from family and classmates who might support my reputation against slander, with a donship hazing in the balance like a gas-mirage.
“I wish I could trust that Stortellen will support her, but… Pleiti, I doubt you follow Modernist scholarship—”
“Very little,” I admitted, with the requisite moue.
“Villette’s research is… very successful, evidently, or they wouldn’t be offering her the donship. But she… well, she’s not very good at playing the loyal scholar, if you know what I mean—values the research itself more than her own prospects, do you see? And the university values it quite a bit more than they value her, if you ask me.”
Again I made a noise of agreement, for this was passing relatable.
“And at the same time there are always people who are jealous or, well, they disagree with her research choices for one reason or another, as if it were any of their business. And I know Villette is determined that everything is fine, and would tell me not to worry, but…” Petanj twisted her hands, then went on with a bit of rue. “Perhaps I am worrying overmuch.”
“Better than worrying too little,” I offered, partly out of sympathy. I, too, was prone to excessive concern, and this scenario was more than enough to unleash it.
“Yes. I would rather be overattentive than regret the opposite. That’s why I’ve decided to go to Stortellen immediately, to check on her—to support her and—and help in any way I can. I would have gone for the donship ceremony anyhap, so this just means leaving a little early. Will you come?”
I stared at her, although surely this was where the whole conversation had been leading. “Er… that is, I’m really not sure I can help in this case…”
“I realize this is not exactly what you have done in your past investigations,” she said in a rush, “and I don’t expect you to be an expert investigator, truly, I—I just would like someone on my side, and perhaps your experience will give you some perspective that I lack. If you would join,” she added somewhat diffidently, “I could talk to Dean Mars. See about working out an arrangement.” One that would mean I was not using my holiday time for this, I supposed. “And of course… if Mossa would—that is, if she has time… But even if she can’t—” She was twisting her hands again, and somehow that decided me. “If you could see your way to join, it would mean so much…”
I was invigorated by a sudden sense more of purpose than of obligation, underpinned by the suspicion that working together with Mossa again might make it unnecessary to address her recent reticence. I handed the laminate back to Petanj crisply. “I’m with you. I’ll go talk to Mossa tomorrow. When are you leaving?”
“As soon as possible. Perhaps tomorrow night? I’ll send you the optimal itineraries.” She tapped them over.
“Well then,” I said, with more assurance than I felt. “I’ll be in touch.”
Chapter 2
It wasn’t until I was on the brief railcar ride to Sembla (after a rather restless night and a few tasks that took up much of the daylight portion of the diurnal) that I counted up how long it had been since I’d been in the same room with Mossa. Perhaps I hadn’t allowed myself to notice before; looked at squarely, it was certainly too long. Terrifying how quickly that gap had sidled into what I had thought of as a positive-trending, reasonably healthy relationship. We both had jobs, we lived on different platforms: we usually saw each other once, maybe twice in a week. Easy enough, then, for a few postponements with reasonable grounds to extend into more than a month of absence.
I tried to think back to the last time we met: Had I done something wrong? Disgusted her somehow? But ponder as I might, I could identify no moment of coolness, no fissure or argument. Perhaps it was nothing, and this distance really was the chance conjunction of mishaps.
Or perhaps it was nothing, and that was enough, because it didn’t always require something happening to fall out of love.
It was full night when I arrived in Sembla, gaslights burnishing the metal of the platform, Ganymede glowing large in the sky. I hoped, as I ascended the ramps to Mossa’s apartment, that she was still on this diurnal; her job sometimes required her to switch, but even back in university she had been liable to moods in which she lost track of time and slipped from one schedule to the other without recognizing the décalage.
My emotions floated as I saw the gleam of light from within outlining her door, and I knocked with perhaps more enthusiasm than necessary.
There was no answer, and I knocked again, calling out softly as I did to identify myself.
Silence.
Starting to feel worried—about Mossa’s safety, now, as well as about her regard for me—I called out again: “Mossa?” My voice quavered and I started to consider how I could get in if she was hurt.
The lock clicked.
That was the remote key, and so when I pushed the door open I expected to see Mossa, as I had so many times before, standing at her desk in the alcove on the far side of the sala. Instead, she was sprawled on the divan, playing something intricate and quiet on her kinnor.
“Mossa!” I exclaimed, and then immediately modulated my tone, trying to fit the timbre of her music. “Are you well? We’ve a mystery to investigate.”
She turned her eyes from the ceiling towards me without haste, and I had a brief fantastical fear that they would be blotted black, or bleeding, but her gaze seemed usual enough, if heavy-lidded. “Pleiti.” Her voice was heavy too; perhaps she had been on the point of sleep when I arrived. I approached the divan, decelerating as I saw the detritus of empty glasses and unorganized laminates around it. And books, piles of books, and no fewer than three teapots on various surfaces, spouts ringed with tannin. She was wearing a silky garment I had seen before, more of a chemise than a robe. It must have had some sensory or talismanic significance for her, because I had noticed she wore it for comfort. (It had a sensory significance for me as well, although I wouldn’t have tagged it as comfort.)
“Mossa,” with more caution this time, “are you well?”
“Well. Well, Pleiti. Well enough.”
I peered at her eyes in sudden alarm that my intrusive horror had been a premonition, but no, her pupils seemed normal; if she was altered, it was by her usual addictions: narrative, tea, music. “Come on then,” I said, my cheerfulness tinny. “We’ve been asked for our help with a little matter, off in Stortellen, which should be entertaining—”
“No.”
I couldn’t think of anything to say but No? and Mossa hated meaningless repetition, and I repeated myself meaninglessly so often, maybe she hated me or maybe I was changing myself for her and that was a mistake or maybe I hadn’t changed enough or—
“I’m not going to Stortellen.” Lower: “I have no help to offer.”
I swallowed. “It will be— The problem is an interesting one, actually, I think you would— That is, you remember Petanj? And her cousin Villette?” I held out the laminate I had brought with my notes from the conversation. “They have a spot of difficulty, a delicate matter. Surely—”
“No.” Mossa felt around for something on the floor without looking, hoisted up three glasses before she found one with liquid in it. “Not. Going.”
“You don’t want to?” My voice rose plaintively on want, irradiate it all, I knew I shouldn’t be like that, I was falling into the failed patterns of university as though we’d never left them (had we left them?). I should try something different, put a slap in my tone instead: Get up this instant! But I couldn’t, I couldn’t order Mossa around, not convincingly.
I put the laminate on the table and dropped into a crouch beside her instead. “Mossa. I can see you’re feeling a bit… a bit Jovian…” Too tentative, she was already scoffing.
“Pleiti, I am not going to Stortellen. I am not going to help. You can go, or you can stay here—though if you do I’d thank you to take yourself to the other room and leave me alone—but I am not going anywhere.” She closed her eyes and tilted her head back against the curling armrest of the divan. The lamplight flickered on the skin of her throat.
I left.
I could have stayed and argued more. Almost as soon as the door closed behind me I wished I had. But truly, what would be the point? I knew well enough that I would not change her mind.
By the time I reached the station in Sembla (where, tiresomely, I discovered a wait of almost an hour for the next railcar that stopped in Valdegeld), I was wishing I had stayed not to convince her, but just to stay with her. But (I recalled after about twenty minutes of pacing), she had exiled me to the guest room in the event I did stay, and there was no reason to think I could have suaded her from that decision either. How long would it have taken before I cracked the shell of her apathy?—If apathy it was; what if she was feeling disdain or, or repugnance? And meanwhile, Petanj who had asked our help, Villette still subject to whatever vile rumors and perhaps discredit, perhaps worse… No.
Still, for the entire slough of my wait on that andén, I could not help but hope for the sudden sound of my name unexpectedly close by, or a silent, sardonic presence beside me. I glanced over and over towards the wide and curlicued arch at the entrance to the station, and I was the last to board my railcar when it finally arrived, standing by the corridor window even when it arrancó, hoping against all expectation to see a slight figure hastening towards us. But Mossa did not come, and before the next daybreak I was on my way towards the farther reaches of Giant without her.
Excerpted from The Potency of Ungovernable Impulses, copyright © 2025 by Malka Older.