A/N: I'm a bit apprehensive about this, because I find it hard to make AU situations work, but I tried. Someone on tumblr gave me the prompt that Stiles has to stay with Erica on her first full moon. I absolutely adore Sterica, and I really hope the TW writers develop them. I mean, "you make a good batman"? I died from cuteness. Anyways, as always reviews would be very appreciated.

Stiles was just about to turn the keys into the ignition of his car when he heard it. A low, throaty growl that could only come from one source. The specific source that had recently caused his life to become an insane, chaotic frenzy that was like something out of a first-rate supernatural teen film. He sighed, and felt his body involuntarily tense. Looks like he would be even later to Lydia's party than he already was.

Hesitantly, he peered from the window towards the back of the car, half-expecting to see Scott and half-expecting to see someone ready to rip his head off. It was the latter.

Erica stood on Stiles' driveway, breathing hard, eyes glowing amber. Stiles groaned. Sure, he'd handled feral werewolves before, but on Scott's first full moon, he'd been chained beforehand. Granted, he escaped the chains, but he hadn't gone after Stiles. And then the next time, he'd been in a box.

Now there was a potentially murderous werewolf standing outside his locked (at least there was that) jeep and Stiles had no way of protection. It was past dusk, and the night was starting to fully set in. He got out his phone, ready to call for some help, when he saw the animal ferocity drain from Erica's face in his rearview mirror. Her claws retracted, and her face went white. Once she started to sway and stumble a little, Stiles hurriedly unlocked his car door and climbed out.

"Hey, hey," Stiles said, catching Erica by the arms so she wouldn't fall. His heart was pounding in fear that she would turn again, but he knew he couldn't just leave her on the driveway of his freaking house, much less have her do something crazy and be spotted by someone.

"Stiles…" Erica mumbled. "Derek's been knocked unconscious… fairy dust or whatever. Lydia."

Stiles frowned in confusion. "What the hell are you talking about?"

Erica groaned, sounding like she was in pain. "He tried to keep us locked up… in a bus, but, I got out. Didn't know what I was doing… came here by instinct."

Instinct. But why would she come here by instinct? Stiles wondered.

Wait. Derek's been knocked out by fairy dust? What the hell was that? And what was Lydia doing…?

Stiles immediately fumbled for his phone and called Scott; he picked up immediately, sounding frantic.

"Stiles, where are you? The punch here has made everyone hallucinate and- we can't find Lydia!"

"Yeah," Stiles said grimly. "We've definitely got a situation. I'm with Erica and-"

"Erica?"

"She came over here in some sort of heightened werewolf instinct- I don't know, man, but the reason she even reached me was because Derek's been knocked out and it has something to do with Lydia."

Scott growled in frustration, sounding very much like a werewolf even though Stiles knew he was in human form. "Okay, we're going to have to deal with this- Stiles, stay with Erica, it's her first full moon. She could kill someone."

"Dude- are you serious? Yeah, she could kill someone- that someone being me!"

"Stiles, you have to take care of it- just, lock her up like you did me that one time."

"Yeah, because that worked out well." Stiles sighed and hung up, aware that he had no control over the situation. He shot a wary glance at Erica, who was currently looking at the sky with apprehension.

"It's getting late, Stiles; I won't be able to control myself soon." Erica's eyes met his own, and for a second he thought she looked almost scared, but there was also a fierceness about her that he realized he admired. He did admire Erica, no matter how crazy she seemed sometimes.

"Right, uh, okay, I'm going to have to chain you to the heater in the basement," Stiles said. "And then I'm going to lock the basement door, because let's face it, you are probably going to break that chain. And maybe knock down the door. And maybe kill me. This should be fun."

Erica rolled her eyes. "Can we just do this already?"

Erica winced at the tight grip of the chains on her wrists. Stiles paused.

"Don't go easy on me," Erica insisted. "Make it as secure as possible. I can handle this."

Stiles gave a half shrug in agreement and fastened the chains closer to her skin. He glanced at his watch. It was a little after eight.

"I'm going to have to leave," Stiles noted, mostly to himself. He looked at Erica then, and saw she probably didn't hear him because she was breathing faster. Her head was lowered down, long blonde curls covering her face.

"I don't… I don't want you to leave," Erica mumbled.

"What?"

"I don't want you to leave," Erica repeated, looking up at him. Her eyes were mixed with desperation and something else Stiles couldn't place.

Stiles stared at her. "Are you crazy? Erica, let me remind you that my quick wit is the only thing I have to defend myself with-"

"Look, I know why it was instinct for me to come here," Erica cut him off. She looked a little pained and… embarrassed? Like she didn't want to admit something. "It was instinct because I knew you could calm me down."

Stiles frowned. "I… don't understand; how could I calm you down?"

Erica huffed. "Derek told Isaac and Boyd and I that there was something that could pull us back to our human side. An anchor. And I… think I figured out what my anchor is."

"Your anchor? What- Okay, what does that have to do with your sudden plan to kill me-"

"Goddamn it, Stiles!" Erica snapped. "You're my anchor, okay? You!"

This left Stiles speechless (a rare occurrence), his mouth slack. Color rose a bit in his face. "…Oh," he said finally. "Uh, well… I'm glad I can help? Er- but I really don't think me being in the same room is going to-"

"Ugh!" Erica grunted suddenly; her breathing became more labored as her eyes turned golden and her nails began to grow and her face morphed. "Stiles… it's-"

Stiles jumped back, looking hurriedly around the basement for something he could defend himself with, and then realized it would be useless anyway.

"Erica, calm down, just- just think of… me? Okay, that sounds really weird -"

Erica growled, shaking the chains on the heater with ferocious strength. The heater shook as well. Stiles looked to the floor in dismay, the idea suddenly coming to him that Erica could harness enough force to rip the heater off entirely. Shit. He hadn't really thought of that before.

"Look, I'm sorry but-"

Erica gave another loud particularly scary sounding growl.

"Okay, yep, I'm out of here." In his classic scrambling fashion, Stiles stumbled up the basement stairs and locked the door, leaning against it and breathing hard.

For the next five minutes, he heard nothing but violent thrashing and werewolf noises, until in an instant it was eerily silent. Stiles listened hard, but he could hear nothing.

This was starting to feel like Scott's first full moon, when the noise had ceased and Scott had been let loose. But there was nowhere for Erica to go.

"Uh… Erica?" Stiles called, hand on the door. He unlocked it and crept slowly down the stairs, ready to flee if necessary.

Erica was lying against the heater, arms slack and full of cuts from her struggle against the heavy chains. In her right hand was a sweatshirt. Stiles raised an eyebrow, realization flooding into him.

"Is that…?" he trailed off.

"Your sweatshirt," Erica mumbled. "Yeah. I told you… you calm me down."

Stiles stood there, honestly stunned that he had that much of an effect on her. He was surprised he left that big of an impression on anyone, much less a girl whom he had barely paid attention to before she turned. And maybe that was the problem. He had barely paid attention to her.

I used to have the worst crush in the world on you. Yeah, you, Stiles. And you never once even noticed me.

Stiles swallowed hard at the memory. He still wasn't sure how to process that confession. Before, he wasn't even sure if he should believe it, but now…

He sat down on the foot of the stairs. Erica did not have any more incidents until dawn; she just leaned against the heater, the rumpled red hoodie clutched in her hand, and Stiles stayed with her the whole time.