Warning: this chapter is all about Gaius giving Merlin The Talk, and then Merlin and Bo beginning their new 'relationship', so naturally it's all a little (by 'a little' I mean 'extremely') awkward. Merlin is torn between his desire to trust her and fear of ending up like her previous victim, and Bo's struggling to find her footing too since she's never been with anyone quite like him.

Merlin returned home to find the guard's body gone - some old books had replaced it on the table - and Gaius pacing in apparent agitation, though he stopped as soon as he heard his ward come in. "Merlin," he said with obvious relief, "did you find the succubus?"

"I did. It was the Lady Isabeau." Merlin couldn't keep a note of smugness from his voice; it felt good to be vindicated after Gaius had dismissed his suspicion of the lady in question.

"Well, it appears your misgivings about her weren't without cause after all. Have you destroyed her?"

"No."

It took a moment for the word to register, and when it did, Gaius thought his old ears must have failed him. "What was that, Merlin?"

"I didn't kill her. She isn't evil, Gaius; she did not mean to kill that man, and she wants to do better. I'm going to help her," he declared, staring Gaius down as if daring him to argue. No matter what the old physician said, he wasn't going to be talked out of helping Isabeau the way he'd been talked out of helping Morgana. He couldn't just send her off to a druid camp even if he wanted to; as she'd pointed out, the difficulty of leaving Camelot unseen made sneaking out every time she needed to feed an untenable option. How often do succubi have to eat anyway? I need more information…

Finding his tongue again, Gaius asked, "And how do you plan to do that?" reminding him that he had to convince his mentor he hadn't gone crazy before he could turn his attention to measuring the succubus' metabolism. "You can't change her nature."

"I know that, but I can prevent her from harming the people of Camelot. We made a deal - I'll keep her secret, she'll keep mine, and she'll leave everybody else alone and only feed on me."

Once again stunned into speechlessness, Gaius couldn't voice what he thought of this deal, but his expression said it all.

"My magic gives me some protection from her powers," Merlin explained in a rush, "and she said she's able to feed without killing, and…do you think it'll hurt very much?"

Gaius felt a stab of pity - the warlock was obviously scared, even if he hid it fairly well - but he stamped it out. Merlin had to learn there were consequences to his impulsive decisions, and the recent episode with Morgana had evidently failed to teach him that. "I doubt it. Merlin, didn't the dragon tell you what succubi feed on?"

"Chi, he said. They…they suck the life out of you…somehow…don't they?"

"Did he say anything else? Anything about how they do that?"

"No…well… He did mention that they can be…seductive-" Merlin broke off, flushing slightly. "That's just how they lure their prey, though, right?" Isabeau would have no reason to employ such tactics with him since he'd already agreed to share his energy with her.

"I'm afraid a succubus' powers of seduction serve a greater purpose than that. Once you told me what manner of creature we were dealing with, I did some research which reaffirmed my knowledge from the days when I regularly encountered such things. I never met a succubus - they're not one of the more common fae, but that's beside the point."

"And what is the point, Gaius?" Merlin asked nervously.

"That succubi drain the energy on which they sustain themselves during the act of…ah…carnal intercourse. I suppose that's why the dead guard looked so happy. …Merlin?" Gaius asked worriedly. The boy seemed to have stopped breathing, and his already pale face was alarmingly bloodless. "Breathe, Merlin." Gaius thumped him on the back, forcing out whatever air remained in his lungs, after which Merlin automatically inhaled. Gaius steered him to a seat near the fire and waited for him to recover from the shock he'd just endured.

At last, when he could speak again, Merlin haltingly asked, "Does this mean…that Isabeau…that she and I… I'll have to…do…that?"

"I assume so."

"But I don't love her, Gaius, I hardly know her!" Merlin buried his face in his hands. "How am I supposed to…you know…with someone I don't love?"

Gaius patted his shoulder sympathetically. "Since your arrival here, you've done many difficult and dangerous things to protect Camelot. Try to think of this as just another of those things, although in comparison to some of the other tasks you've been forced to undertake, this should prove to be a more agreeable experience."

###

Agreeable - yeah, right. More like awkward and embarrassing, probably. Merlin had gone back to bed on Gaius' advice, but the knowledge that he had inadvertently acquired an inhuman lover made sleep impossible. At least the Lady Isabeau looks human - she's actually quite pretty… Everyone says so, even Arthur, and the prat is right for once. It had to happen sometime.

In fact, Isabeau's - Bo's, she wanted him to call her Bo, he reminded himself while rolling his eyes at the ridiculous name - good looks might be problematic. Merlin knew he couldn't allow himself to lose sight of what she was, because if she proved incapable of controlling her appetite in accordance with their bargain, she would have to be put down, but looking past a façade as pretty as hers to the creature underneath wasn't easy. In that one brief, confusing moment in which she'd leaned over him, those perfect lips barely inches away from his, the fact that she wasn't human had almost slipped his mind completely. Part of him, Merlin realized now that he had a chance to revisit the moment in his mind and analyze his feelings, had almost been excited about kissing her, and that excitement wasn't entirely due to the thrill of impending danger.

He rolled onto his back, staring up at the ceiling, which was now illuminated with the first faint light of dawn, without really seeing it. The idea of a creature that kept itself alive by stealing the life force of others was repulsive; the succubus herself was anything but, which left Merlin not knowing how to feel about her. Was he doing the right thing by trying to help her, or making the worst mistake of his life? Did her nature mean she was destined for evil, or was she capable of fighting it and doing good? She frightened him, but as the sky outside his window continued to lighten Merlin came to the realization that he was less afraid of what feeding her would require from him than of the possibility that he might actually like it.

###

The lovely succubus stayed in his thoughts throughout the first half of the day - much to the annoyance of Arthur, who kept asking where his mind had gone - then, at lunchtime, she showed up in the flesh, accompanied by Kenzi. "What up, warlock?" the human girl asked with her usual exuberance as she swept into Gaius' workspace in a whirl of black hair and satin, tugging Bo by the arm like a pull-toy.

Gaius jumped up and shuffled as fast as his legs could carry him to close the door Kenzi had thrown open. "My lady, now that you're aware of Merlin's magic, I must impress upon you the importance of keeping it secret."

"I know, I know - Uther, magic ban, head-chopping-off, bad." Kenzi made a slashing motion across her throat with a finger. "My lips are zipped, but c'mon, there's no one here but us."

"Still, you never know who might be listening, so please refrain from shouting about magic at the top of your lungs."

"Dude, that was my inside voice. Has Gaius got one giant-ass bug up his skirt or what?" she whispered in an aside to Bo, then continued, "Anyway, half of what I say seems to go right over people's heads; Arthur actually said he doesn't understand me, but I'm starting to think Arthur's a few fries short of a Happy Meal, if you know what I mean…"

Bo nudged her in the ribs, reminding her why they were there.

"Right, so…" She spun around to face Merlin. "Bo told me about you guys' little arrangement, and I personally think she's gone Bo-nanas, 'cause I'm not feeling any sparkage here. Still, as Dr. Hot Pants would say, you have to disprove a hypothesis before discarding it." Bo looked askance at her. "Hey, I didn't like the woman; doesn't mean I never listened to her."

"I told you I don't need to feed again so soon," Bo objected.

"And I told you we should make sure sorcerer chi does it for you before you get hungry for realz."

"You're here for…feeding?" Merlin asked, his mouth suddenly dry.

"Yup, time to put up or shut up, magic man." Kenzi pushed Bo toward him.

"Okay, wow, this is weird," Bo mumbled as Merlin slowly stood up and approached her. "Just relax; this won't take long. You can close your eyes if you want to." Like having blood drawn, chi extraction might be easier if you didn't watch it happen.

Merlin shut his eyes, but they popped open the instant he felt her take hold of him, and he found himself staring into unnaturally bright blue succubus eyes. Those eyes were probably the last thing that guard saw before he died. Images of the dead man's face, that grotesque smile on his desiccated lips, filled Merlin's mind and he panicked; he didn't want to end up like that man. Who would protect Arthur if he died, he hadn't gotten to see Arthur crowned king yet and the prat most likely wouldn't survive long enough to be crowned without him, and what would his mother think if his body was brought to her looking like that, how would they explain his death to her, what would she do…?

"Hey!" Bo let go of him and took a step back, giving him a look of profound frustration. "How are you doing this!"

"Is there a problem, my lady?" Gaius asked.

"Yes, there's a problem - he's blocking me somehow!"

"Ooh, tough guy - does this make him the first one to ever really make you work for it? But then most guys aren't scared of you, and Merlin's kinda got this look-" Kenzi paused to mimic his expression "-like you're a dentist coming in for a root canal."

"Really?" Bo's glowing eyes dimmed as she turned back to Merlin. "Is Kenzi right? Do I scare you?"

"Yes."

"What! Why? I'm not scary…am I?"

"Only in a femme fae-tale way. Seriously though, compared to some of what's out there, our Bobo's a lambchop," Kenzi assured Merlin. Her words didn't quite have the comforting effect she was aiming for.

Bo ran her hands over her face as the last of the blue faded from her eyes. "Okay, if performance anxiety's the problem, we can work on that. Kenzi, Gaius, can you give us the room? We're gonna need some privacy."

"I have work to do here, but Merlin's bedroom is just up there." Gaius helpfully pointed the way.

"That works too. Come on, Merlin."

Merlin shot Gaius a wounded look, wondering how his guardian could have offered him up like some sort of sacrificial lamb so easily. Gaius just arched an eyebrow at him as if to say, You're the one who told her to feed on you, Merlin. You have no one to blame but yourself. This, unfortunately, was perfectly true, so he reluctantly followed Bo up the short staircase leading to his room.

She stopped to look around upon entering, taking in every detail of the small room. "Huh. So this is your place."

"It is, my-" She scowled at him. "-Uh, Bo." Her scowl turned into an approving smile. "It's not as luxurious as what you're accustomed to-"

"Don't worry about that. I've been in some places so crappy you wouldn't even believe it. This is fine, although…" She picked up his nightshirt off the floor, where he'd dropped it while rushing to get dressed that morning. "Seriously?"

"Sorry. I'll just…" He took it from her and stuffed it into a cupboard. When he turned around again, she was standing by the door, which she had closed.

"Look, Merlin, are you sure you want to do this? You're obviously not into it, or me-"

"I don't want anyone else to get hurt."

"The whole idea is that it's not supposed to hurt."

"That includes you; I don't want you to get caught, because Uther will execute you. I don't know why protecting you matters to me, but it does. Maybe I just want there to be one magical creature in the world that isn't evil…" If a succubus could be reformed, that would make the dragon's warnings about Morgana's inevitable descent into darkness much easier to ignore, or maybe his desire to believe Bo was or might be a good person was rooted in Morgana's apparent fondness for her. He didn't want Morgana to get hurt or fall prey to a bad influence.

"I'm not," Bo insisted. "I'm not perfect - I've done plenty of things I regret, but I always tried to do what I thought was right. I wish you could see that being fae doesn't define me - it's what I am, not who I am."

"I believe you…at least, I think so," Merlin said cautiously.

"Great, so what're you afraid of?"

"Ending up like that guard. Did you see his body after you were done with him? I did. It was horrible. Also, Gaius told me how you feed, and I don't think I'm ready for…" He waved his hand in an expansive gesture that took in Bo and the bed.

She looked around blankly; then, at last, comprehension dawned. "Oh, you mean sex? I guess that's understandable if you haven't been with a fae before. But you don't need to be nervous; it's basically just like being with a human."

"I wouldn't know."

"Why not? You've done it before, haven't you?"

Bo meant the question to be purely rhetorical, so she was shocked when Merlin replied, "No, I haven't. I did kiss Gwen once. Well, actually she kissed me."

"Gwen kissed you," Bo repeated tonelessly. "That's it? What have you been doing all this time?"

"Saving Arthur's life so he can become king one day. When I'm not doing that, I'm washing his socks or polishing his armor. I haven't really had time for girls."

Bo sighed. "Shit, I usually don't do virgins."

"Why not?"

"Because you don't know what you're doing." She stalked across the room and sat down on Merlin's bed. "Come over here. Relax - I'm not gonna jump you. We can take it as slow as you need to; succubi feed on their partner's pleasure, so I want you to enjoy this. Come on."

Merlin hesitantly sat beside her. Bo smiled. "Good boy." She ran her fingertips over the back of his hand. "How's this feel?"

Her touch sent a slight shiver through him. "Why is your skin so hot?"

"It's supposed to take the edge off," Bo explained, frowning. "Don't you feel anything?"

Merlin nodded. "Heat."

"You're not fighting me again, are you?"

"I don't mean to."

After a minute or two and several deep breaths, some of the tension left him. Bo suspected he wasn't completely under her control yet, but she finally felt him responding to her touch. Leaning forward, she let her lips brush his. He accepted the contact, so she kissed him in earnest, molding their lips together while keeping it light and gentle, like a caress. By the time they separated, his resistance was weak enough that Bo thought she could smash through whatever barriers remained. She didn't, though; she'd never gotten off on forcing her partners. She wanted him to give in to her willingly.

"See, that wasn't so bad, was it?"

"That was amazing. Are you…finished?"

"No, that was just a kiss; I didn't take anything. I'll try that now, if you think you're ready." Merlin's heart sped up, so Bo channeled more of her power to calm him. "It won't hurt, I promise. It'll feel just like what we were doing before. I just need you to trust me."

Merlin swallowed hard. "I trust you."

She kissed him again, closing her eyes so he wouldn't freak out if they changed color. This time his chi poured out in an unobstructed rush, flooding into her and burning its way down her throat like Trick's finest liquor, except Trick had nothing this strong on his shelves. If her first kiss with Dyson had been like fourth of July fireworks in her mouth, this was a supernova.

"Isabeau? My lady, are you all right?"

She laughed. "I am spectacular, and you are one hot-shit wizard. I mean, damn! I think I'm a little buzzed… Why're you looking at me like that?"

"Your eyes…well, take a look for yourself."

Bo shot to her feet, relishing the feeling of power that surged through her body with every movement, and went to the window to check out her reflection. Her eyes were so bright that they actually radiated blue light, bathing her face in a weird illumination.

"Does that always happen after you feed?"

"No, this is new." She shut her eyes and tried to will herself out of succubus mode, only to find when she reopened them that they were still lit up like icicle lights at Christmas. "Okay, what's the deal here? I've never tasted chi with such a strong kick, and I've fed on some pretty powerful fae. What are you?"

Hey, feeding on the world's most powerful warlock had to be different from Bo's average snacks, right?

Next up: Kenzi asks for Merlin's help with a problem, and our favorite dragon has a few things to say about Bo.