The serum burned through my veins like liquid sunlight.

I gritted my teeth against the pain, watching my hand blister in the shaft of late afternoon light streaming through the laboratory window. The skin bubbled, turned gray, then began to smoke.

Thirty seconds. That was all I'd gained from two hundred years of research.

I yanked my hand back into shadow and reached for the syringe of counteragent with fingers that trembled despite two centuries of practiced control. The needle slid home. Relief flooded through me as the antidote worked, skin knitting back together in seconds, leaving only the memory of agony and the acrid smell of burned flesh.

Failure. Again.

I documented the results with mechanical precision, my handwriting perfectly steady now. Iteration 247: Subject experienced second-degree burns within thirty seconds of UV exposure. Cellular degradation rate: unchanged. Conclusion: Failure.

The word tasted like ash in my mouth.

My laboratory occupied the sub-basement of what had once been a tuberculosis sanatorium, all stone walls and reinforced doors that could withstand anything short of a nuclear blast. The perfect place for a monster to play scientist. I'd filled it with state-of-the-art equipment, climate controls, and enough redundant power systems to keep my research running through the apocalypse.

The irony wasn't lost on me. All this technology, all this knowledge, and I still couldn't solve the fundamental problem of my existence.

I couldn't walk in the sun.

The intercom crackled. "Dr. Thorne? Your four o'clock appointment is here."

Dr. Simone Chen's voice carried the carefully neutral tone she used when discussing my "special dietary requirements" with potential donors. We'd worked together for five years now, ever since I'd approached her with my proposal: I would provide experimental treatment for her terminal patients, and in exchange, they would provide me with the fresh blood I needed to metabolize my daywalker serum.

A transaction. Clean. Clinical. Nothing like the hunting I despised.

"Send him down," I said, already closing my lab notebook and securing the failed serum in its refrigerated vault.

This would be my last donor. The hospital ethics board had grown increasingly uncomfortable with my presence, despite the hefty grants I provided. They wanted me gone by the end of the year. Six more months to crack two centuries of failure.

I should have felt desperate. Instead, I felt numb.

The elevator descended with a mechanical groan. I caught the scent before the doors opened—cedar and rain, undercut with something darker. Illness. The sweet-sick smell of cells devouring themselves from within.

Cancer.

The man who stepped into my laboratory was dying, and he wore it well.

He moved with the careful economy of someone managing pain, but his shoulders stayed straight, his gait steady. Late thirties, lean in the way of men who'd forgotten to eat rather than those who chose not to. Dark hair showing premature gray at the temples. Green eyes that catalogued everything with the sharp attention of someone used to looking for the story beneath the surface.

Those eyes fixed on me and something flickered in their depths. Recognition, though we'd never met.

He'd seen death before. He recognized a fellow traveler.

"Dr. Thorne?" His voice carried a rough edge, like whiskey over gravel. "Marcus Reid. I'm here to be your juice box."

Dark humor. I appreciated that.

"Mr. Reid." I gestured to the medical chair I'd positioned near my desk—far enough from the windows to be safe, close enough to the equipment to monitor vitals. "Please, sit. We'll start with the intake questionnaire."

"The one where you ask if I understand I'm volunteering to let a vampire drink my blood?" He settled into the chair with a slight wince he tried to hide. "Yeah, I read the waiver. Signed it in triplicate. Had it notarized. I'm very committed to this terrible decision."

Despite myself, my lips twitched. "You'd be surprised how many people get cold feet at this stage."

"I don't have enough time left for cold feet." He met my eyes directly, no flinching from the amber glow I knew brightened them in artificial light. "Stage four pancreatic cancer. Six months if I'm lucky, three if I'm not. Your experimental treatment won't save me, but Dr. Chen says it might give me a few extra weeks without feeling like garbage. I'll take it."

The casual acceptance of his own mortality should have made this easier. It didn't.

I pulled up his file on my tablet, scanning the medical history I'd already memorized. Marcus Reid, former photojournalist. Fifteen years documenting war zones, humanitarian crises, the worst humanity had to offer. No family. No spouse. No one who'd miss him when he was gone.

Perfect donor material.

I hated that I'd thought it.

"The process is straightforward," I said, slipping into my clinical voice. "I'll take approximately one pint of blood during each session. You'll experience some dizziness, possible euphoria from endorphin release. The sessions will occur three times weekly for the duration of your treatment."

"And you'll use my blood to... what, exactly? Dr. Chen was vague on the details."

"I'm developing a serum that would allow vampires to tolerate sunlight." I saw no point in lying. He'd signed the NDAs. "Fresh human blood is required to metabolize the compound. You provide the blood, I provide experimental pain management and possible extension of your quality of life."

"Experimental pain management." He huffed a laugh. "That's a hell of a euphemism for vampire venom."

He'd done his research. Also surprising.

"The endorphins released during feeding have shown promise in managing chronic pain," I said carefully. "Some donors report a significant improvement in their final months."

"Yeah, I read the testimonials. Vampire hospice care. It's either the most humane thing I've ever heard or the most fucked up." He rolled up his sleeve, exposing the pale underside of his wrist. "Guess I'll find out which."

The scent of him intensified—cedar and rain and that underlying warmth of living blood. My throat constricted. When was the last time I'd fed? Three days? Four? I'd been so focused on the serum trials I'd neglected the basics.

Dangerous. Stupid.

"Not the wrist," I said, my voice rougher than intended. "The femoral artery is more efficient."

His eyebrows rose. "That's... intimate."

"It's anatomical." I stood, moving to prepare the monitoring equipment. Anything to put distance between us and that scent. "I need you to remove your pants."

A beat of silence. Then: "You know, I always imagined a beautiful woman saying that to me under different circumstances."

Heat crept up my neck—an autonomic response I'd thought I'd killed decades ago. "Mr. Reid—"

"Marcus. If you're going to bite my thigh, we should be on a first-name basis."

"Marcus." I turned to face him, letting him see the full weight of my amber gaze. "This is a medical procedure. I need you to treat it as such."

He held my stare for a long moment, something unreadable flickering across his features. Then he nodded and stood, unbuckling his belt with practiced efficiency.

I busied myself with the monitoring equipment while he stripped down to his boxers, giving him the illusion of privacy. When I turned back, he was settled in the chair, one leg extended. The scent of him nearly buckled my knees.

Control. Two hundred years of control.

I approached with clinical detachment, kneeling beside the chair to position the pulse oximeter on his finger, the blood pressure cuff on his arm. His skin radiated heat—that impossible warmth of the living that I'd forgotten I could miss.

"Baseline heart rate: seventy-two," I murmured, checking the monitors. "Blood pressure: one-twenty over eighty. Respiration: normal." I met his eyes. "This will hurt, briefly. Then it will feel... pleasant. Try not to move."

"I've been shot twice and survived a building collapse in Aleppo. I think I can handle a vampire bite."

"You've never experienced this."

I placed one hand on his thigh, feeling the muscle tense beneath my palm. The heat of him seared through my cold skin. My fingers found the artery, feeling the steady pulse of blood beneath.

My mouth watered.

I leaned in, breathing in the scent of him—cedar and rain and something else, something vital and alive and utterly intoxicating. My lips brushed his skin.

He sucked in a sharp breath.

"Hold still," I whispered against his thigh.

Then I bit down.

The first taste of blood exploded across my tongue like starlight, like summer, like every beautiful thing I'd forgotten existed. Rich and complex, carrying notes of copper and salt and something indefinably Marcus. I felt his body jerk in surprise, then go still as the venom hit his bloodstream.

I'd fed from hundreds of donors over the centuries. Thousands, maybe. I'd learned to take only what I needed, to keep it clinical, controlled. A transaction. Nothing more.

This was nothing like that.

This was drowning in sunlight.

The blood sang through me, setting every nerve ending ablaze with sensation I'd thought long dead. I could feel his heartbeat against my lips, could taste the adrenaline spiking through his system, could sense something deeper—memories, emotions, the essence of who he was bleeding into me with every swallow.

A child laughing in a garden. The weight of a camera in his hands. Smoke and screaming and the terrible beauty of a city burning. The cold certainty of a doctor's diagnosis: I'm sorry, there's nothing more we can do.

I jerked back, gasping.

That shouldn't happen. I'd perfected my technique decades ago—take the blood, leave the soul. Clean extraction. No connection.

But I could still taste him, still feel the phantom echo of his memories rattling around my skull.

Marcus stared up at me with dilated pupils, his chest heaving. "Holy shit."

My hand shook as I pressed gauze to the wound, applying pressure. "That's... a normal reaction."

"Normal?" He laughed, breathless. "I just saw my entire life flash before my eyes and it felt good. That's not normal."

I couldn't argue with that.

I focused on the practical, checking his vitals with hands that had steadied through sheer force of will. Heart rate elevated but not dangerously so. Blood pressure stable. Color good—better than good, actually. The grayish pallor I'd noticed when he arrived had faded, replaced by a healthy flush.

That was wrong too. Donors were supposed to look worse after feeding, not better.

"How do you feel?" I asked, still not meeting his eyes.

"Like I just did a line of the world's best cocaine while having the world's best orgasm." A pause. "Not that I have recent experience with either, but the memory's pretty clear."

Despite everything, I felt my lips twitch. "The endorphins will fade in a few hours. You may experience some fatigue. Dr. Chen will monitor you overnight."

"Elara."

The sound of my name in his voice made me look up. His green eyes held mine with an intensity that made my dead heart clench.

"You're standing in sunlight."

I froze.

He gestured to the window behind me, where the late afternoon sun streamed through in golden shafts. I'd been so focused on him, so overwhelmed by the feeding, that I hadn't noticed.

I was standing directly in a beam of natural light.

And I wasn't burning.

I stared at my hand, turning it slowly in the sunbeam. The light caught on my pale skin, making it glow like alabaster. No smoke. No blisters. No pain.

Just light.

"Your serum," Marcus said quietly. "It worked."

Had it? The iteration I'd tested an hour ago had failed spectacularly. But I'd fed since then. Fed on him. And now...

I looked at Marcus Reid—dying, mortal, impossible Marcus Reid—and felt something shift in my chest. Something that felt dangerously like hope.

"We need to run tests," I said, my voice barely above a whisper. "I need to document this. I need to—"

"You need to admit that's fucking amazing," he interrupted, a grin spreading across his face. "Two hundred years, right? That's what Dr. Chen said. Two hundred years of trying, and you finally did it."

I wanted to share his enthusiasm. I wanted to feel the triumph of finally, finally succeeding after centuries of failure.

But all I could think about was the taste of him still coating my tongue, the memories that shouldn't have transferred, the way his blood had felt like coming home to a place I'd never been.

Something was wrong.

Something was very, very wrong.

And I was going to need more of him to figure out what.