"Drink some water", Stiles said and handed Derek a cup of water. The situation slowly seemed to calm down. Selena had passed out and Scott had taken her to his room, where Melissa took care of her. Stiles was worried but Scott ensured him, that she just needed some sleep and that she didn't feel any pain anymore. Derek had passed out right after they came back from his mind. He had just woken up and suffered from a bad headache.

"What the fuck happened in there?", Isaac suddenly said and was brave enough to say out loud, what Scott and Stiles were both thinking. Derek glared at Isaac from his seat, but put the cup of water down anyway. He took a deep breath and told them what his mother had told him and Selena. Dereks voice was steady and calm but Stiles noticed the crack in his voice when he told them, that Selena was his sister and that they had known each other their whole lives.

"Did she mention the alpha?", Isaac asked, but Derek shook his head no. He placed his fingers on his temples and moved them slowly, hoping it would make the headache go away.

"So, if Selena takes the alphas power, she can give it back to you. And as soon, as you're an alpha again, her powers will fade again. That sounds like the perfect solution to me.", Stiles concluded and placed one of his fingers on his chin while he got lost in his thoughts.

"Yes, if she's able to do it. I don't know how to teach her control it or to take the power at all. Or does any of you want to play the guinea pig?" Derek looked at Scott, then at Isaac but they both didn't answer. They both didn't want to risk the chance of losing their powers forever, and Stiles could think of only one person that would actually deserve it.

"Peter." Stiles turned around to see who had expressed his thoughts and saw Selena standing in the doorway. He felt the urge of running up to her, hug her and then kiss her again, but something about her made his body freeze. Selena looked angry. Not angry enough for her eyes to glow, but angry enough to seem more supernatural than human. Stiles felt a sharp pain in his chest when he noticed, that she was avoiding his gaze.

"Do you even know Peter? Don't you think he's well... too smart and too strong to play the guinea pig for you? He will kill you before you can count to three.", Isaac said and slowly backed off, when Selena walked up to him.

"Just because you are scared of him, doesn't mean that I am. He killed people. He killed my sister. If I'm going to take anyone's power, then it will be his. With or without you.", Selena hissed and stared at Isaac with angry eyes.

"And how exactly do you want us to do that? He's smart.", Scott stated and flinched when Selena turned her head to him, her eyes suddenly glowing. Stiles didn't say anything, but he was sure that in this moment, they were all more scared of Selena, than they had ever been of Derek.

"Fool him, use wolfsbane, Kanima venom or whatever. I don't care, just do it."

"Selena...", Derek tried but Selena shook her head.

"Lydia is picking me up, she's taking me back to Allison. Just... do something about Peter.", was all she said before she left the room. The boys looked after her and breathed out, after they heard the front door slam shut. Selena wasn't herself and she reminded Stiles of Scott in his first night of the full moon. Something, he didn't want to experience again.

"What should we do now?", Scott asked but looked in three clueless faces. Everyone knew that Selenas idea was based on revenge and anger and that Peter was too smart for them to fool him. But in the end, it was the only plan they had. Just like that, Derek went back to his loft, thinking of a plan to make Peter get there. Isaac, Scott and Stiles drove to the animal clinic to get wolfsbane and kanima venom. Right after the sun was faded, they all found themselves at Dereks loft with Peter infront of them, chained up and unable to move.

"That was way easier than expected.", Isaac said and crossed his arms over his chest, staring at Peter. Peter rolled his eyes and sighed.

"What the hell do you want?", he asked and looked at his nephew who leaned against a table.

"Scott?", was all Derek said and looked at the younger boy. Scotts eyes glowed red when his fingers turned into sharp claws. Without any hesitation, Scott pressed his claws in Peters neck, making Peters eyes glow blue. Scott showed him, whatever they had seen in Dereks mind, giving him back his memories. Peters body healed way faster than Dereks and Selenas had.

"That's a freaking joke. A goddess of the moon. In our family?" Peter didn't look surprised, he just looked like he was completely done with his family. Or the whole world.

"You being a werewolf is a fucking joke.", Selena muttered and walked up to him.

"Selena, wait. We should think of something, before you start...", Scott began but Selena already reached out for Peters arms. Her grip around his arms tightened when her eyes changed to a glowing silver. The second Peters eyes started to glow, Selenas muscles tensed and her face looked like she was in pain. The pain seemed to get worse, when she suddenly screamed and took a few steps backwards, losing the grip on Peters arms. Stiles was about to walk up to her when he saw, that her legs and arms started shaking. Selena ignored her body though and took a few steps closer to Peter again. She closed her eyes and breathed in deeply before gripping his arms again. Nothing changed though, with every passing second, she just felt more pain. Selena didn't seem to care though, she kept trying it again and again.

"Selena, stop it!" Derek suddenly screamed and pulled her back by her shoulders. Selena turned around to him with anger in her eyes.

"I have to do learn it, right? I don't have a choice!"

"Yes, but not without knowing how. Let us help you." Dereks voice sounded calm again, but Selena just shook her head.

"Nobody here has got any clue. You can't help me." With that, she made her way back to Peter, repeating the same thing again and again. With every failed try, she got angrier, until the room was filled with aggression and revenge. There was nothing left that felt human, there were no emotions.

"She lost control.", Allison said and watched Selena losing herself.

"Maybe she needs an anchor.", Scott mumbled and noticed Derek looking at him.

"Scott, she's not a werewolf.", Derek reminded him but Scott shook his head.

"Maybe she's more like us than we think. She uses anger too. Without an anchor, no humanity. Without humanity, you can't judge rationally. She won't make it, if revenge and hate is all she can think of, that's against nature. She needs humanity to make it." Derek understood what Scott was thinking and nodded.

"She will listen to an alpha howling then." Scott nodded slightly and closed his eyes to shift. He opened his red eyes and howled loudly. Stiles could feel the floor shaking and saw how Isaacs eyes light up golden. Selena turned around and looked at Scott.

"Selena, you need an anchor to control it. Look for an anchor that will make you feel human again.", Scott said and looked right in her silver eyes. Selena seemed confused and turned back to Peter.

"Oh my god, guys. She already has an anchor, just tell her how to use it.", Allison said and rolled her eyes, probably regretting not taking Lydia and Kira with her.

"It's Stiles. Tell her to think of Stiles.", Allison explained and Scott nodded again, getting Selenas attention again.

"Selena, think of Stiles.", Scott growled and looked at Selena like it was a command.