"Listen, I — I have to go. She's coming. Bye."

Quickly I end the call before Aldous can say anything else. Especially before he can inquire too closely about how I obtained my latest information. I don't really know just how much time I have before Cosima returns, but surely it won't be much longer; the nearest store is only a few blocks away.

I look around her rooms, panicking a little because I'm not totally certain I've returned everything to its previous state. Her apartment is small, though the high ceiling and numerous windows and skylights give the impression of spaciousness. She has occupied this place for only a few months but already nearly every surface is covered with books, papers and knickknacks; the clutter is intensely personal in a way that makes a curious kind of organic sense. The furniture and decor are all in a mix of the rich dark colors I've come to associate with her. It's a far cry from the comparatively expensive but soulless downtown flat assigned to me when I started working for Dyad, the flat that I spend as little time in as possible and for which I have done nothing to make my own. I have already resolved not to bring Cosima there if I can avoid it.

Piles of books occupy the floor in the corners and nooks, landsliding and interweaving in precarious strata that I dared not disturb during my hasty search lest the whole arrangement come crashing down.

"How do you find anything in here?" I'd wondered aloud yesterday evening — was it really only yesterday? — when I'd visited her home for the first time, looking around as she'd frantically finished dressing for dinner amidst discarded clothing heaped on her bed, draped over furniture, puddled on the floor.

She had graced me with that smile, the disarming one that starts out shyly and curls almost reluctantly outward until her entire face is alight. "There's a system, believe me."

"Chaos is a system?"

Her nose had wrinkled adorably. "Very funny. All right, I'll prove it to you. Ask me where anything is."

I hadn't been able to resist the impish charm of the challenge, or the challenger. Quickly I'd reviewed the conversations we'd had since my first contact with her a few days prior. "Ummm, okay. Newman and Müller."

"Ppbbbbbbtttthhht. Way too easy. On top of the toaster oven." She'd pointed to the area by the windows that was set up as a rudimentary kitchen. Sure enough, there sat a battered and extensively tabbed copy of Origination of Organismal Form.

"You make a habit of keeping books on top of the toaster oven?"

"The last time I needed it was for a citation for my paper on post-replicative DNA methylation for my Advanced Tissue Mechanics class the other day." I must have looked confused — or possibly mesmerized by the elegant gesticulations of her hands — because she'd smiled again. "I was starving because I'd forgotten to eat dinner that night. I was going to make some toast but didn't realize until it was too late that I was out of bread. The only thing in the pantry was a box of Lucky Charms, so I ate like three bowls standing at the counter and reading. Didn't want to get the book wet while I was washing up the dishes, so I stuck it there. See? Makes perfect sense."

I'd had a hard time keeping a straight face. "But what if you want to make toast now? Where would the book go?"

"No prob. I'm still out of bread."

Not for the first time, I'd noticed that the tip of her tongue poked out from between her teeth when she was on the verge of laughing.

Dropping in today, when I clearly had not been expected, confirms that Cosima's idea of housekeeping is more than a little loose. Which is something of an advantage when it comes to trying to hide the evidence of my subterfuge, but I know better than to presume that she won't notice that her things have been moved.

I need a diversion. And under these circumstances, in this situation, there's only one sure way that I can think of to pull it off.

After a last look around, I get back in bed, arranging the duvet and pillows and myself just so. My pulse is racing, my stomach muscles aching with tension. Years of scientific training do not exactly prepare one for maintaining a duplicitous mentality and carrying out acts of espionage. Or, not to put too fine a point on it, for whoring oneself out for one's employer. For Aldous.

I'll sort that out later. Along with making sense of what I've discovered.

Not about her research, there's nothing to question there: her work is meticulous, neatly and logically arranged, almost freakishly so in contrast to the appealing disorder of her home.

Learning that she's aware of and been in contact with so many of her genetic identicals has been stunning, of course, but it's nothing compared to the revelation that none of my previous lovers has ever made me feel as good, as cared for, as worshiped as Cosima has tonight. And that I find her absolutely enthralling, any qualms I might have had about being with a woman vanishing with that first searing kiss we'd shared this afternoon.

All of which makes my guilt at deceiving her in this manner so much worse, like a thousand paper cuts to my conscience.

Aldous said she's in danger, I tell myself firmly. It's my responsibility to find out as much as I can about her, to get close to her, to find out what I can do to help her.

The bed is soft and warm and smells delightfully of her. After a while I begin to relax, the adrenaline surge finally subsiding. I've almost drowsed off by the time I hear footsteps again out in the hallway, the floorboards of the old Victorian house ringing beneath her heels. The door opens without the warning preamble of a key turning; my heart skips a beat at the thought that she hadn't even bothered to lock it behind her, that anyone could have walked in on me while I was searching her place. The sounds coming from the other room tell me that she is dropping her things and removing her shoes. I force myself to remain still, listening to her bare feet padding over rugs toward the bedroom alcove. "Wake up, sleepyhead, epic deliciousness awaits — whoa." A sharp inhalation, followed by a long measured release of breath. Then, almost reverently, "Dude."

I put on a deliberate show, stretching lazily before rolling over onto my back to look up at her and making no effort to hide my naked body. "Did you miss me?"

The expression on her face is gratifying and I know instantly that my diversion is a success. She's standing as if rooted at the foot of the bed, wearing only the bra and panties she'd thrown her coat over before leaving, a canvas shopping bag dangling forgotten from one hand. Her mouth opens and closes a few times, and then she swallows audibly. "Yes, but apparently I had no idea just how much." Recovering, her eyes sweep lingeringly and appreciatively over me, a smile stealing across her lips. "You look a bit more comfortable now."

"I just felt that there was no point in being modest after — well, after. Don't you agree?"

It takes her a few seconds to get my meaning. She shakes her head a little as if to clear it, her dreads bouncing and frisking with the movement. "Totally." Tossing the bag onto her desk, she reaches behind her back to release the clasp of her bra, letting it fall to the floor to reveal small but nicely shaped high rounded breasts; her nipples are already hardened into dusky points. Watching me watch her, she slips off her underwear and kicks the scrap of cloth aside, doing a gracefully unhurried pirouette so that I can admire her lovely compact form from every angle.

Stopping to place her glasses on the nightstand, she climbs into bed beside me and envelops me in a full-contact kiss. Her slender frame fits perfectly against me, our height difference erased, legs tangling, hips instinctively beginning an insistent press and slow grind. The sweetness of her mouth is now redolent of an earthy, citrusy, faintly bitter and pungent flavor I haven't encountered since CPGE. I smile. "I think I know what took you so long."

"Busted." Cosima chuckles, leaning her forehead against mine. "I found an old pinner in my pocket. Didn't mean to lose track of time, but it was such a primo little hit." She kisses me again, the tip of her tongue sweeping lightly inside the curve of my lower lip, then retreating. "For future reference, Casey Jones goes perfectly with smart hot blondes."

"'Blondes,' plural?" I narrow my eyes at her in a mock glare.

She arches an eyebrow into a perfect circonflexe. "Blonde, singular. Specifically the singularly gorgeous, brilliant, fascinating, delectable blonde currently occupying and immeasurably improving my bed."

"I'm glad to hear it. I don't think I'm capable of fighting off any competition at the moment."

Fingers wind into my hair, pulling me into another kiss. "No competition whatsoever," she murmurs against my lips.

"Good." Gently I encourage her to lie back, raising up on my elbow so I can see her face, brushing with feather-light strokes of my fingertips along the precisely shaped brows, the warm smooth curve of her cheek, the rounded tip of her nose, the outline of her mouth. Her hand slips to the back of my neck, tugging, but I shake my head with a smile. "I want to learn your skin."

She lets her hand fall, smiling up at me, her nearsighted eyes a little unfocused but shining. "Do your worst, Beraud."

The name jolts me like a sudden electric shock. I had completely forgotten that my Dyad cover was my mother's maiden name, the name that was on the fake transcript I had left behind in the MicroBio lab to engineer our introduction. To hide the pause, I let my hand trail lower, caressing the tendons along her neck. Softly I press my lips to the satiny patch at the base of her throat that just barely contains her pulse, feeling the increase of her heart rate and the subtle vibrations of a muted sigh when I swirl the tip of my tongue there.

I learn many interesting things. I learn that her left nipple is more sensitive than her right, and that licking and sucking and biting its pebbled surface makes her writhe and squeal like a puppy. I learn that she is ticklish when I kiss the insides of her upper arms or flick my tongue at her belly button, and that the sound of her laughter delights me absurdly. I learn that she has a hidden tattoo, a small representation of the THC molecule etched into the hollow of her right hipbone, and that even though it is years old she says the skin there still tingles when I trace the outline of the chemical bonds. And I learn that her patience is finite, and that when pushed past her limit she becomes ferocious, devouring and possessing, fiercely and singlemindedly determined to make me lose count of the number of times she brings me to screaming, panting, frenzied orgasm.

At some point I must have passed out because I wake up wrapped bonelessly around her, my face nestled into the curve of her neck, one leg slung over hers. My entire body feels limp, wrung out from an excess of pleasure, aching and sore and pulsing in all the right ways.

Lips brush my forehead. "You doing okay?" I can hear the smile in her voice.

I press a soft kiss to her throat, taking in with my mouth the scents of sex and clean sweat and the indefinable essence that is hers alone. "Do you have to ask?"

She laughs, a low and husky rumble. "Considering that you slept through complaints from two of my neighbors, probably not."

"Sorry."

"No, you're not."

I smile, nipping the side of her neck. "No, I'm not."

She has thoughtfully left a glass of water for me on the nightstand; gratefully I drink it, then settle myself once again into her arms. Smooth blunt nails scratch lightly over my back in lazy patterns. I stretch against her like a cat, arching into her touch.

"Cosima, do you play any musical instruments?" I say after a long comfortable interval, turning on my side to face her.

She blinks. "Piano, for a few years when I was a kid. Why do you ask?"

"I might have guessed that. You should take it up again; you have such beautiful hands." I reach for one of hers, rubbing my thumb over the palm.

"I wasn't all that good. Didn't mind practicing, but I never liked performing. Recitals were a nightmare — I used to puke my guts out right before it was my turn to play. Around junior high I decided the world needed a top class scientist way more than it needed another third-rate pianist." She moves to mirror my posture, propping her head on her elbow. "What about you?"

"Cello, from the time I was small. I still play occasionally, mostly for myself or when I have the chance to get together with a group of friends."

Her mouth curves into a grin. "That's why you have those little calluses at the ends of your fingers."

"Yes, though they're much less prominent than they used to be. These days I don't play nearly as often as I would like to." I place my hand on her forearm as though on the neck of my instrument, fingertips dancing and pressing lightly, thumb sliding gently over the logarithmic spiral of the nautilus tattoo on her wrist as I shift positions.

She giggles. "What are you playing?"

"The Prelude to Bach's Suite no. 5." I keep it up for a few more phantom bars, then lean in to kiss her. She tastes of me, my come smeared liberally all over her face and mingling with the last traces of the joint she'd smoked hours ago.

It's enough to start my pulse hammering again.

"The reason I brought it up, my little insatiable minx," I say, nibbling at her lower lip, "is to demonstrate that playing cello results in the development of superb agility, independence, flexibility and coordination of the fingers of the left hand." Waggling those fingers at her, I drop my hand to her chest, circling and teasing each breast in turn, then caress the incomparably soft skin of her belly, moving slowly but inexorably lower.

She's breathing faster, her hips beginning to churn. "Is that so?" Lying back, she lets her thighs fall open in clear invitation.

I brush the top of her mound, barely skimming damp-darkened curls. A brief investigation of her folds confirms that she is just as wet and hungry as I am. "That, my dear Cosima," I murmur, easily sliding three fingers into her astonishing heat, "is most definitely," I hook the tip of my pinky inside the ring of her ass, wriggling it and making her quiver with every minute tug, "so." At that I circle the pad of my thumb over the glassy surface of her plumply swollen clit.

Her hips vault off the bed, inadvertently impaling herself even deeper on my fingers. I am literally holding her in the palm of my hand.

Avidly I drink in every moan, every raucous gasp, every swivel of her pelvis as my fingers twist and plunge and curl within her, awed by the rawness of her response. Sweat breaks out over her body as she arches into the rough rhythm of my thrusts, almost sobbing for breath. Unable to resist, I bend my head to press a kiss to her sex, hesitantly at first, then more confidently as her cries escalate into inarticulate howls. She tastes of sweet and salt and musk with a hint of a metallic tang, bathing my mouth and hand in fragrant slickness. Remembering something she had done for me, I trap the slippery scarlet bundle of her clit between my lips and lash at it with my tongue. Instantly I am rewarded with a hoarse shriek, her hands gnarling into my hair and not so subtly urging me to increase the pressure. The rolling of her hips becomes frantic; with my shoulder I wedge against the powerful tensing of her thighs that threatens to pulverize my hand. Ever so carefully I scrape the edge of my teeth over her bursting clit. The added stimulation proves to be her undoing as she thrashes and jerks and leaps, keening as her shudders are prolonged by the unceasing diligence of my tongue and fingers.

When the quakes and thousands of little aftershocks have stilled within her at last, I free my hand and drape myself over her, bracing on my elbows to kiss her gently for long minutes until the ragged hitch of her breath deepens and slows. "You sure you've never done this before?" she says when she can talk again.

"May I remind you that you already asked me that earlier. The answer is still n = 1," I say, unable to hide my smugness.

"Now who's being cheeky?" Playfully she swipes her tongue over my chin, then all around my mouth, licking off the copious evidence of her arousal. "I've never dated a musician. There was Tommy Donovan for a while in college, but he was a drummer and those guys are like a completely different species. Little did I know I should have been checking out the string players in the orchestra instead." She smiles at the look on my face; I've never been good at disguising my feelings. "Don't be so surprised. I've been with men before. Even almost got engaged to one, about a hundred years ago when I was young and stupid. Not to mention completely stoned on Bubba Kush. I swore to stick mostly with the sativa strains after that."

"I guess... I just assumed you were a lesbian."

The corner of her mouth quirks. "Not into labels, dude. Technically I suppose I'm bi, but really... well, for me, the point is not whether I desire women or men sexually, but rather that it is possible for the person I desire sexually to be either a woman or a man. It's a subtle but crucial distinction. So there's, like, a boatload of traits and qualities I look for in someone I'm attracted to, but gender isn't one of them — it's just not on that list. Shit!" She scrabbles at me, pushing me aside so she can sit up.

"What? What is it?" I say, startled and dismayed at the abrupt change in her demeanor.

"The ice cream!"

I fall back into the pillows, laughing helplessly. Cosima leaps nimbly out of bed and snatches up the abandoned shopping bag from her desk. She pulls out a brightly colored cardboard package; using her thumbnail to slit open the flap, she peers cautiously inside, poking experimentally with one finger. "Hmm, kind of squishy. I think these need to chill out for a while." Stashing the box in the tiny freezer compartment of her mini fridge, she saunters back with a sheepish grimace. "Sorry, Delphine, guess you'll have to lose your Eskimo Pie cherry later."

Still laughing, I welcome the press and warmth of her into my embrace once again. We're both far too tired to do more than kiss and snuggle; eventually she falls asleep, one arm flung across me, her hand resting along the curve of my ribcage below my breast.

"Tu m'enivres, et je t'adore à la folie," I whisper into her hair. She mumbles in her sleep, burrowing closer. Something in my heart expands, and I know with absolute certainty that whatever danger threatens her, whatever she has to face, I will do anything and everything in my power to help her and keep her safe.