Here she was, the freaking head of an assassin den, master of more than three dozen highly skilled killers, and she’d been summoned like some lowlife imp to an audience with her brother. The great demon doctor. She’d already given him her blood, her DNA, her pee, her spinal fluid… whatever samples the doctor wanted for his research, she’d handed over. Sin was, after all, responsible for the disease that was wiping out the werewolf race.

What a claim to fame.

A couple of days ago, she’d even come into Underworld General to channel her power into an infected male in an attempt to kill the virus, but if anything, she’d only accelerated its spread. And she hadn’t thought it could get any worse. Sin muttered to herself as she traversed UG’s dark hallways on the way to Eidolon’s office. Her boots clacked on black stone floors that were unusually in need of a good sweeping, and the echo bounced in eerie vibrations off the gray walls. She trailed a finger over the writing on said walls— protective antiviolence spells scrawled in blood. She had to give credit to her brothers for that; the hospital serviced nearly all species of demons, many of which were mortal enemies.

She rounded a corner to enter the administrative area, only to curse fiercely. Wraith, the only one of her four brothers with blond hair and blue eyes—neither of which were original parts—stood in the doorway as though he’d been waiting for her. His arms were folded over his broad chest, the dermoire on his right arm blending in with his T-shirt’s Celtic print—Celtic print that was cleverly designed to form the words “Fuck off.”

“Well, if it isn’t Typhoid Mary.”

“Read your shirt.” She pushed past him to enter the office, missing a step when she saw not only Eidolon, MD, but also Conall, SOB. Great. When she’d last seen the vampire-werewolf a few weeks ago, they’d parted on shitty terms. He’d assumed the worst of her, threatened her, had been an utterly unlikable ass. Oh, sure, she’d led him to believe she’d intentionally started the epidemic that was killing his warg relatives, but if he hadn’t been such a jerk, she might have told him the truth.

Not that the truth was much better. “Sin.” Eidolon remained at his desk, his espresso eyes bloodshot and framed by dark circles. His short, nearly black hair was mussed, probably from repeated rakes of his fingers. He pretty much looked like hell itself had beaten the crap out of him. “Sit.”

The command ruffled her feathers, but she hooked a chair with her foot, yanked it as far from Conall as possible, and planted her ass. “What now? I don’t have any blood left, and if you think you’re getting a stool sample, you can—”

“I don’t need a stool sample,” Eidolon interrupted. “I need your help.” She felt Con’s silver eyes boring into her like drill bits, and to her annoyance, her body flushed with warmth as though remembering another drilling he’d given her. That was so not happening again. “Look, you should know that the Assassin Guild has been flooded with requests for hits on wargs. I don’t know if the sudden surge is related, but I figured I’d tell you.”

Wraith’s sharp gaze cut to Eidolon. “I’ve heard the same thing. Word on the street is that some of the other were-species are worried that the wolves will transmit the disease to them, so they’re being a little… proactive.”

Both Eidolon and Con uttered the same raw curse.

Sin settled back in her chair and forced herself to stay calm, when all she wanted to do was scream at this disaster she’d created. “You said you needed my help. What kind?” Eidolon reached for the water bottle on his desk and took a swig before speaking. “Thanks to Harrowgates and the ability to travel instantaneously, the virus has now made its way to every continent except Antarctica. The death toll is climbing. The disease has a one hundred percent mortality rate, a practically nonexistent incubation period, and no victim has lived longer than seventy-two hours after infection. Basically, by the time a patient arrives, we don’t have a lot of time for treatment.”

Jesus. It was worse than she’d thought. “Haven’t you made any progress at all?” “A little.” Leather squeaked as Eidolon leaned back in his chair. “We’ve discovered a half-dozen wargs who were exposed but didn’t contract the infection. The R-XR is trying to determine what makes them immune.”

The U.S. Army’s paranormal unit was involved now? And Eidolon was working with them? She’d known that their brother Shade’s mate, Runa, used to be a member, and that Runa’s brother Arik still was, but holy crap—it just didn’t feel right for the government to be involved in any way with Underworld General.

Especially not a military unit that killed, captured, and experimented on demons. Then again, UG had several strong ties to The Aegis, a civilian demon-slaying organization—hell, Eidolon was even mated to an Aegis Guardian—and so far, the association had benefitted both UG and The Aegis.

“So I’m here, why? Are you in need of assassination services, or what?” She threw that out just to get a reaction from her uptight, always-in-control brother, but to her surprise, it was Con who made the noise.

“You’re here because wargs are dying, and it’s your fault,” he growled, a hint of an odd British-ish accent tweaking his words. It happened when he got all pissy, and it was strangely… hot. But she still didn’t like him, and she wrenched her head around to peg him with a glare. Which might have been a good plan if he hadn’t looked so damned good in his black paramedic uniform, which set off his deeply tanned skin and sun-streaked blond hair so beautifully. Toss in those shimmering silver eyes, and there was no glaring at him. Only admiring.

“Why are you even here?” she snapped, more irritated by her reaction to him than anything. “I didn’t think the disease affected dhampires.” “I’m on the Warg Council. I’m keeping them informed.”

“Well, good for you.”

Eidolon cleared his throat imperiously. “Actually, you’re both here for a reason. Sin, it’s time that we put some serious effort into working with your gift. We’ve got to determine a way to use it to treat the disease.”

“We tried that before. My ‘gift’ kills. It doesn’t cure.” Her “gift” was something she’d really like to give right back to her Seminus father. Too bad he was dead.

“Yeah, well, technically, you shouldn’t exist, so I’m not ready to write off the impossible.” Oh, she loved the reminders about how she was a freak of nature, the only female Seminus demon to ever have been born. A Smurfette, as Wraith liked to call her.

“So what’s your plan?”

“Can you use your gift to determine what kind of disease resides inside a body? If you touch someone who is ill, can you tell what they are sick with?”

“Sort of. I can feel the arrangement of the virus or bacteria or whatever. And once I learn it, I can replicate that specific disease.” She shot Conall a smirk. “Khileshi cockfire is a favorite.” Wraith laughed. Conall paled. Eidolon looked at her like she was responsible for every case of the excruciating, dick-shriveling venereal disease he’d ever treated. The guy was so freaking uptight he probably starched his freaking underwear.

“As disturbing as that is,” Eidolon said flatly, “it’s exactly what I wanted to hear.” There was a tap at the door, and Lore strode past Wraith, who was still playing doorjamb sentinel. Lore held a folder in his leather-gloved hand, and Sin didn’t think she’d ever get used to seeing her twin brother in scrubs. “I read the R-XR’s initial report on the immune wargs, and something jumped out at me. The wargs who didn’t catch SF after being exposed were born wargs. So I examined the bodies in our morgue and ran some tests. I know not every warg that’s been infected has come through the hospital, but the ones who have? Turned wargs.”

Sin frowned. “SF?”

“Sin Fever,” Wraith chimed in a little too enthusiastically.

Sin Fever? They’d named the f**king disease after her? Bastards.

E flipped excitedly through the folder Lore gave him. “Just when I thought we’d never find a link between the victims. I’ll call the R-XR and let them know. Excellent work, Lore.” Despite the grim subject matter, Sin couldn’t help but be thrilled that her brother, who had, as an assassin, known nothing but killing and loneliness until just weeks ago, was now mated, happy, and working in the hospital—the morgue, where his death-touch couldn’t accidentally kill anyone.

“Wait,” Sin said. “How can you tell the difference between turned and born werewolves?” “Born wargs usually have a birthmark somewhere on their bodies, but we can’t always go by that.” Before Sin could ask why, Eidolon finished. “Outcasts are required to have them removed, and some turned wargs have them artificially applied, so we have to perform genetic testing to determine if they’re born or turned.”

Huh. Who would have thunk it? “So, what was it you wanted with me?”

Eidolon looked up from the paperwork, and the circles under his eyes seemed to have lightened a little. “About that… see, that’s why I called Con to this meeting.”

Bracing his muscular forearms on his knees, Con leaned forward in his chair. When he spoke, his fangs flashed as fiercely as his eyes. “What are you saying?”

“Your weekly blood tests for SF have been coming back negative,” Eidolon said. “Until yesterday.” “What? I have the disease?” Con exploded out of his chair, but Eidolon held up his hands in a staycalm motion. “Not exactly. It’s in your blood. Your body isn’t attacking it, nor is it attacking you, and you aren’t producing antibodies. But when we introduced Sin’s blood to the mix in the lab, your white blood cells and hers joined forces to attack the virus.”

Sin’s skin prickled with foreboding. Eidolon was dancing around something. “Skip the buildup and backstory. Bottom line, what do you want from us?”

“I need Con to feed from you,” he said with uncharacteristic awkwardness. “And I need it to happen now.”

I need Con to feed from you. Con cursed softly. “As much as I’d like to help you out, Doc, I can’t do what you’re asking.” Yeah, he’d tasted Sin’s blood before—and it had been damned good—but that was exactly why he couldn’t do it again. He’d been addicted to a female’s blood before, and he would never allow it to happen again.

“I get that she’s not your favorite person—”

“He said he can’t do it,” Lore interrupted. “Let it go.”

Eidolon tapped a pencil on his desk, the dull thud of the eraser on wood punctuating his words. “Unfortunately, there’s no ‘let it go’ option. This might be our only shot at an immediate solution.” “I don’t understand,” Sin said. “What do you mean, a solution?” Eidolon spun one of the papers around to show Sin and Con where he’d scrawled a lengthy column of numbers. “I can’t inject the amount of Sin’s blood required to destroy the virus into Conall without killing him. He needs to ingest it. As a dhampire, he has a double-chambered stomach, the second chamber working the way a vampire’s works—to deliver a victim’s blood almost directly into the vampire’s bloodstream. So if my calculations are correct, a normal feeding will allow him to take in enough blood to start attacking the virus. Once that’s done—”

“I can monitor his blood to learn how the virus is killed and then use my power to try to destroy it myself,” Sin finished.

“Exactly.” Eidolon grinned. “You really should be working here instead of as an assassin.” At some point, Sin had produced a throwing knife and was now flipping it between her fingers, and Con had a feeling the speed directly related to her level of agitation. The sucker was whirling like a helicopter blade. “Bite me.”

Eidolon gestured to Conall. “That’ll be his job.”

“No,” Con said grimly. “It won’t. There has to be another way.”

“I agree.” Sin rose to her feet, her blue-black hair swishing angrily around her waist. “I don’t let anyone fang me.” You let me, you little liar. Hot, little liar. Man, Con wanted to call her out on exactly how she’d let him, but at least two of her brothers in the room were a little on the overprotective side, and the other didn’t need an excuse to kill things. Come to think of it, none of them needed an excuse.

Neither did Con. “If there was any other way,” Eidolon said, “I’d find it. But there’s not.” He wadded up a sheet of paper and tossed it at the overflowing garbage can in the corner. “You have the virus—it’s just not attacking you, and I don’t know why yet. It’s a slightly different strain from what’s attacking the wargs… it’s adapted to your species, but it might be trying to mutate into something that can attack you, which is why we need to eliminate it as soon as possible. As for the wargs… that’s what was so weird about the blood samples the R-XR took. It was as if the uninfected wargs were a different species and unable to catch the virus.”

“You mean like how horses don’t catch measles from humans,” Sin said, and Eidolon nodded. “Exactly. I still don’t know what would make born wargs so different from turneds.” The frustration in Eidolon’s voice was echoed in his expression as he turned to Con. “And you, even with your vampire status, you’re somehow more closely related to turned wargs than born ones.”