Unfaithful: An unputdownable and absolutely gripping psychological thriller Read online

  I look up.

  “Nothing, why?”

  “You’re smiling.”

  I plaster on my most innocent face. Puzzled, sincere. If I could, I wouldn’t just say it out loud, I would scream it from the top of my lungs. Because when I suggested this committee, I didn’t know that Alex—my Alex, my PhD student—was about to prove one of mathematics’ most important conjectures. And once Alex and I publish our paper, donors will be falling over themselves to throw money at us. That’s how important this paper is. It’s groundbreaking, and marvelous, and it’s the best thing to come out of Locke Weidman University, ever. And while it’s absolutely Alex’s work, as Alex’s advisor, I can say I am responsible, in my own small way, for that achievement. I imagine Geoff’s face when he finds out that I am co-author of a groundbreaking paper that is going to bring googolplexes of dollars to our university. I mean, let’s face it, the last time I published anything was a comment on a working moms’ Facebook group about a one-pot recipe: My whole family loved it! 5 stars!

  I shake my head. “Nope, all good, as you were.”

  He winks at me and turns back to the board. “Okay then.”

  Alex had come to study at this little university because of me, he said. He had stumbled upon a paper I had published a million years ago, back when I was a grad student myself, and had walked into my office brandishing a copy of a now-defunct mathematics journal. He wanted me to supervise his thesis which, at the time, was on theta and zeta functions. He’d had offers from other universities, some certainly more prestigious than ours, but: “I must do it here, with you,” he’d argued.

  My first impression, from the way he looked and the way he spoke, was that he would have been more at home at Princeton than at our humble institution. He’s athletic, very handsome, with fair hair and when he smiles, which isn’t that often anymore, I always find myself staring at his teeth, so perfect, so white.

  Was I flattered that very first day? Absolutely. Did I want the extra work? No. But he wore me down, with his big, pleading blue eyes and his earnest face.

  “Please, Dr. Sanchez! You’re the only one that I want!”

  I’d laughed, and he smiled in that seductive way of his, all teeth and charm, like he already knew he’d won. And he had, I guess, because I said yes, because he did spike my interest, and because it is nice to be wanted.

  It was immediately obvious that he was bright. I mean, really bright. But, like a lot of geniuses, he’s also obsessive. He can spend days poring over a minute and insignificant detail. It’s as if he can’t differentiate what’s important from the trivial. He also gets distracted easily.

  After he’d been working on his chosen topic for a few weeks, he came to my office, closed the door, sat down and said, “I have to tell you something.”

  We didn’t have a meeting scheduled but that never bothered Alex. He just comes in whenever he likes and if I’m sitting with another student, he’ll wait outside, tap his foot against the door jamb loud enough for us to hear, cough, make a nuisance of himself until we’re done, or until we give up.

  “What is it?” I asked.

  “You have to promise to keep it secret.”

  I rubbed my forehead. “I can’t promise that. What have you done?”

  He looked sideways and sighed.

  “Did you get drunk? Do something you regret? Did anyone get hurt? Do we need to speak to student services?”

  “Anna! Are you for real? Is that the first thing that comes into your mind?”

  “Just tell me, Alex.”

  He handed me an ordinary spiral notebook—Alex does all his preliminary work on paper, which is not that unusual.

  I opened it. The writing was messy, full of crossed-out equations and shorthand notes, but I knew how to read it, and it made my stomach twist. I stared at it for a long time, and for a moment I wondered if he was playing a joke on me.

  “Can you tell what this is?” he said.

  I couldn’t even look at him and I couldn’t speak either. The Pentti-Stone conjecture. A famous problem, unsolved, first proposed in 1905 by mother and daughter mathematicians Claudia Pentti and Noemi Stone. Then the world forgot about them until an American billionaire and futurist called Leo Forrester resurrected them. His foundation awards prizes to innovative discoveries and he’d stumbled upon the Pentti-Stone and realized that if it were solved, it would revolutionize too many things to list, from computing power to aircraft design.

  The reason I knew so much about the Pentti-Stone was because of my mother. She was a scientist and I was an only child who turned out to be a bit of a math prodigy, an aptitude I nurtured and generally worked very hard at because it felt like it was the only thing she liked about me. If I had to describe my mother, I would say she was cool, strict to the point of austere, and not very motherly.

  When I was fourteen years old, my mother assigned the Pentti-Stone problem to me as some kind of punishment for sneaking out one night and going to a party I hadn’t been allowed to go to. That summer, when my friends were hanging out by the river, going to the mall, having sleepovers, I was at my little desk trying to solve a math problem that had grown men punching the wall in frustration. But that was the deal, she’d said. If I could solve it, I could go out and play. I didn’t know it was some kind of trick and I spent the entire summer on it, poring over equations just like the ones I was staring at in Alex’s notebook, until my eyes felt like I’d rubbed salt into them.

  I didn’t solve it—that should go without saying—and to this day the very name Pentti-Stone makes me want to bite someone.

  I flicked through Alex’s notebook, numbers blurring as I swiped the pages quickly back and forth, unable to fully absorb what I was looking at, feeling confused by the familiar, the aberrant, knowing I should feel excited by the possibility but feeling devastated instead. Finally, I looked up. He was grinning, and I wanted him to go away. I wanted to say I had work to do, that I had no time for this.

  Then he said it.

  “The Pentti-Stone conjecture. I think I have an angle.”

  He looked nervous, almost frightened.

  “Really?”

  “Yes.”

  There’s a prize too: $500,000 to the first person to prove or disprove the Pentti-Stone. Not as much as mathematics’ Millennium Prize—that’s the big one, at $1,000,000—but not small change, either.

  I stood up to close the door, even though the room felt airless. “You want to talk me through it?”

  He did, animatedly, chaotically and yet beautifully. He hadn’t come up with a complete solution yet, but the work he’d done on his thesis to date had accidentally nudged him in the right direction.

  “I think I can do it,” he said, breathless.

  I paused, willing my heart to slow down. “It’s harder than you think.”

  “I know. I need your help, Anna. Will you help me?”

  Would I help him? My first thought was no. Absolutely not. But how could I say no? What if he found another supervisor? Someone at MIT maybe? Could I bear it? And if I said yes, I could think of it as closing a circle. The end of the work I’d started so very long ago.

  “And I want to change my PhD topic to this,” he continued. “Can I do that?”

  I thought about it. The ramifications were negligible; people changed their topic all the time.

  “And it has to remain secret,” he added. “For obvious reasons.”

  “Obviously.” If it became known at this point, even just within the university, that Alex was close to solving the Pentti-Stone, and especially what his approach was, there was no doubt someone else would jump on it and quite possibly snatch the prize before he did. Us academics might look mild-mannered and geeky on the surface, but underneath we’re a bunch of hyenas who’d do anything for a scrap of recognition.

  “Not even your husband,” he said.

  “Honestly, Alex, Luis wouldn’t know the Pentti-Stone from the Rosetta Stone.”

  “I don’t care. Nobody c
an know, you have to swear. Nobody.”

  I did. I swore. I’m good at keeping secrets, I said. I was already thinking of what it might mean for the university, the research funding we’d be able to attract. This would be a game changer for our faculty. We would join the ranks of the most prestigious academic institutions in America.

  After that, the conjecture was all he could think about, but passion has its consequences: he lost weight, lost sleep, grew dark circles under his eyes.

  We spent months on it, which is not very long in the scheme of things. People spend years, decades, trying to solve a conjecture. He went down rabbit holes a few times. He’d think he was so close, then one detail would make the whole thing crash and he’d have to start again.

  Then he became paranoid that people were spying on his work. He wouldn’t put anything at all in a computer in case we got hacked. He wrote everything by hand and kept it in a locked drawer in my desk, even though he had his own locked cabinet in an office he shared with other students.

  “I don’t trust them,” he said.

  “So, lock it in your cabinet then.”

  “Anna, they’re on wheels!”

  In the end we agreed he could work in my office, which I would lock whenever I was out. I also had a small desk brought in especially for him. It was kind of exhilarating because we made progress so quickly. But when his health deteriorated, when he couldn’t cope with the pressure, he was awful to be around. I dreaded coming to work. He was always angry, sad, desperate. Manic. Then he became resentful of me because he thought I wasn’t doing enough to help him. As if somehow it was my fault he hadn’t solved it yet. Like it was simple multiplication and I hadn’t explained to him how to do it.

  Then he stopped coming altogether. I knew he wasn’t working on it at home because all his notes were in my office. Then one night I woke up in the middle of a dream with an idea. I tiptoed downstairs and called him. I told him my theory. What if…? What do you think? Would that work? Two days later he’d cracked it.

  A PhD thesis can only be authored by the student in question. But we agreed to write a paper together about the Pentti-Stone conjecture and its proof. We’d be co-authors, which was not that unusual between the student and his or her adviser, but to co-author a paper on such groundbreaking work is worth its weight in gold for any academic. His name would be first, there was no question about that. But we would have to be quick. Even though I wasn’t paranoid like he was, ideas have been known to hop from head to head until they find a willing host.

  Often they find more than one, and whoever gets there first, wins.

  Three

  “You look nice today,” Geoff says. The others have gone and it’s just him and me left. He’s packing up his laptop and I’m tidying up the meeting room, making sure to leave it the way I’d like to find it.

  “Do I?” I give a little laugh, turning to wipe the whiteboard so I don’t have to look at him. “That’s nice. Luis thought I looked conservative.”

  He comes up right next to me and takes the block eraser from my hand, puts it down in the tray.

  “What?” I ask.

  He takes my shoulders so that I’m facing him, then reaches for the top of my shirt and swiftly undoes the button.

  “There.” He smiles. “Fixed it.”

  I feel myself redden. The top edge of my plain white bra is visible now, and my first thought is, I wish I’d worn a nicer one.

  Geoff walks away, stops at the door. “See you around,” he says, with a wink.

  I finish tidying the room, a little embarrassed, a little shocked even, yet unable to suppress the small smile playing on my lips.

  Last year, when Geoff and I were away at some conference in Chicago, something almost happened between us. He’d been looking at me like a ravenous wolf all evening and I was flattered, probably more than I should have been. Somehow, I ended up drinking too much, certainly more than I’d intended, and next thing I knew, we were in his room and he’d gone down to his boxer shorts. But I checked out at the last minute. It was as if I’d woken up from a dream, and an image of Carla and Mateo’s cute little faces looking up at me popped into my mind. I excused myself and ran out of the room, and I thank my lucky stars every day that I came to my senses before anything actually happened.

  I was embarrassed the next day, my memory blurry from all the alcohol I’d consumed. I rushed to apologize, although for which part I’m not sure. The part where I almost went through with it? Or the part where I didn’t?

  He laughed. “Don’t worry about it, Anna.” Then he made a show of checking no one was around before leaning forward and in a low voice he said, “Next time.”

  And I laughed. “I don’t think so,” I said, even though I was kind of flattered he still wanted to.

  He made a sad face and put both hands over his heart. “You’re killing me!”

  I chuckled, lightly punched his shoulder. I was so grateful we could laugh about it. I shudder to think what might have happened, but now it’s like a secret joke between us: one time, someone mentioned Chicago in a meeting, and we immediately looked at each other and cracked up behind our hands.

  I make a short detour to see June on the way back from the meeting so I can tell her about the alumni dinner. And I’ll make sure to tell her that it was Mila’s initiative, not mine. I don’t want her to think I’m assigning extra work to her. I’ve almost reached her when Clyde, the associate dean of the college, slaps a sheaf of papers on her desk.

  “For Christ’s sake, June! Are you completely stupid? These are last year’s figures! I asked for this year’s intake! Can you get it right this time?” Then he turns around, mutters something about having to do everything twice around here and marches back down the corridor.

  It was a shocking performance, and if I’d had time to turn away, I would have. But it’s too late now. It would only add to June’s embarrassment. So I stand there, inches from her desk, a smile plastered on my face like nothing’s wrong, or if it is, I didn’t notice.

  She reaches for the bundle with a trembling hand and pulls it slowly towards her. She looks like she’s going to cry with her head down and her black curls falling forward, almost hiding her face.

  “He’s a bully,” I say simply. “He speaks like that to me all the time.”

  I don’t know why I say that since it’s not true. I just want to soften her humiliation. I certainly don’t think Clyde should speak to anyone like that and I make a mental note to pull him up on it later.

  June looks up, crimson patches blooming on her cheeks. She tries to smile, and fails. Her chin wobbles. “I doubt that very much.”

  “You’d be surprised.”

  “It’s not even my job,” she says. “His secretary is off sick and I’ve been asked to step in.”

  I lean forward and whisper, “I searched his desk for a stapler once, and I found a penis enlargement pump. Top left drawer, under that stupid little tray he keeps his paperclips and rubber bands in.” I stand up. “Just think about that next time he talks to you like that.”

  We both know I just made that up. She drops her head and laughs silently, and it takes a moment for her to recover. When she looks up again, the smile is real.

  “Thank you,” she says, still trying, and failing, to stop grinning.

  I wink at her. “My pleasure.”

  I tell her about the alumni dinner proposition, then head back in my office and type up the minutes so they’re ready to email before I leave to meet Alex.

  Then Mila comes in. There’s a guffaw of student laughter outside and she closes the door.

  “Anna, do you have a moment?”

  “Of course, Mila. Please.” I indicate the seat opposite. “How can I help you?”

  She looks skyward, like she’s thinking about it. I wait, my hands knotted together, a benign smile on my face. I’m going for the mentor-to-mentee look, even though I’m wondering if she’s going to ask me to do something. Pick up one of her tasks. Find someone to
mark her exams. Organize the alumni dinner.

  “How can I help?” I repeat.

  “I wanted to tell you myself, make sure you were okay.”

  “Oh?”

  She looks sideways, takes in a small, sharp breath, closes her eyes briefly, and I know now it’s going to be bad. For me.

  “I got the professorship. I found out this morning.”

  I manage to stretch my lips thinly over my teeth and into a smile. My knuckles have turned white and I feel my chest rise and fall as my pulse races. I repeat the words in my head, in case I got them wrong the first time. I got the professorship. Nope, no change, stomach still clenched. I’m trying to think of something to say and we just stare at each other in silence for a while.

  “I didn’t know you’d applied.”

  “Yeah, it was on impulse, really—just a last-minute thing. Geoff suggested it.”

  “He did?” A last-minute thing? It takes weeks, months, to put an application like that together. Is she going to say she wrote the application twenty minutes before the deadline? I don’t get it. Does she want me to feel even worse?

  Then it occurs to me maybe there’s more than one professorship this year after all. Maybe I too will find out today.

  “So they announced it?”

  “This morning. And Anna, let me say that I was completely surprised. Shocked, really. I was sure it would be you, and it should have been you. I don’t know why they gave it to me. I keep expecting someone to tap me on the shoulder and say they’ve made a mistake.” She gives a small, self-deprecating laugh.

  There are probably things I should say, but I can’t speak. It’s like my throat has clammed up and nothing will squeeze by except maybe my last breath.

  “I know you must be disappointed.” She tilts her head at me, checking to see just how disappointed, presumably.

  “Not at all,” I manage, finally. “I’m very”—I was going to say ‘happy’ but it gets caught—“pleased, for you.”