I posted this drabble to tumblr (littlecajunlady) on March 25, 2015 and the prompt was "Looks like we'll be trapped for a while." This would take place after a season 4 where Allison survived.

"Stiles, what are you showing us?"

"I'll show you when we get inside."

Stiles and Malia were leading Scott, Allison, and Isaac into the Hale vault under the guise of needing to "show" them something he and Malia had supposedly found inside. Of course, that was a bald-faced lie. He had other reasons for this.

Malia used her claws to open the vault, and then she and Stiles stepped aside to let the others in. The three walked in and spread out, immediately going over to look at the shelves. Scott was the first to notice that Stiles and Malia hadn't followed them inside, and he turned around to find Stiles putting down a line of mountain ash just outside the doorway.

"Stiles, what in the hell are you doing?"

"Getting you three to define the relationship."

"What?"

Stiles dusted his hands off and stepped further behind the line. He wanted to be unreachable when he said what he did next. "Can we stop pretending that I didn't walk in on the three of you during post-coital cuddles?"

Scott, Allison, and Isaac exchanged awkward glances. Then Scott said, "I told you, it was a onetime thing. It just … kind of happened."

"Well, your onetime thing is making things awkward as hell for the rest of us. So like I said, you three need to, you know," he said, waving his hand at the three of them, "figure all of this shit out."

"Stiles, you know I can get past the mountain ash."

"Not without nearly dying, you can't."

Stiles started to close the door, but then Allison said to him, "And you realize I could walk right out of here, right?"

"Come on, Allison. Can you please be cool? Now, Malia and I will be guarding this door and Derek's got the other one so –"

"Derek knows?" Isaac said, speaking up for the first time.

"Yep, and Lydia knows too," Malia told them. "Though she seemed way more impressed than anything else. She said she thought you three were way too vanilla for that."

All three of them looked offended. Stiles and Malia laughed and shut the door. They all shouted and cursed Stiles's name, but he didn't respond. They were alone.

"I'll indulge him for now, but if they don't let us out in the next twenty minutes, I'm out of here," Allison grumbled. She sat down on the floor. "Why is this any of their business anyway?"

"I mean, we have been kind of awkward around each other lately," Scott said, still not quite able to look the two of them in the eye.

They stood there in silence, too stubborn to speak. After five minutes they heard a bang on the door. "I don't hear you talking in there!" They groaned.

"Looks like we'll be trapped for a while," Isaac said. He took off his shirt and tossed it aside.

"Isaac!" Allison cried. "I don't think Stiles was suggesting an orgy when he came up with this plan."

"Wasn't he?"

Scott finally spoke, but he kept his voice low. "Look, I don't agree with his methods, but maybe Stiles is right. Maybe we should talk about it."

Even though it was Scott's suggestion, neither he nor Allison said anything. Isaac scoffed, "Why are you two making such a big deal out of this? So we had a threesome. So what? Friends have sex with each other sometimes."

They both looked at him with narrowed eyes. Allison said, "I don't have sex with myfriends!"

Scott asked, "What were you, Boyd, and Erica into exactly?"

Isaac shrugged. "What weren't we into?"

"Oh my god." Allison put her head in her hands for a moment. She could think about that piece of news later. She wanted to focus on their issue. "I keep going back to that night. It all just happened so fast. I can't even remember how it started."

They all thought back to their night together two weeks ago. Even though it had been four months since Allison had been stabbed by that Oni, they still hadn't talked about the things Allison had said to Scott when she'd thought she was dying. Once she was released from the hospital, Allison and Isaac had gone back to how things were before her confession, and Scott continued to date Kira until fairly recently, deciding they were better as friends.

That wasn't the real reason they'd broken up, of course. Scott had truly never gotten over Allison and everyone knew it. Isaac could see that Allison certainly wasn't over Scott. She insisted she was, but Isaac thought it was best that the three of them finally got together and talked it all out. What ended up happening that night was Allison admitting she had real feelings for both of them, and Isaac asking why she had to choose.

Suddenly remembering, Allison raised her head and said to Isaac, "It was you. You started it."

"Me? How?"

"You kissed me," Scott said.

Oh, right. That night when Allison had seemed confused by his question, he'd said, "I just mean, if you want to be with both of us, then why can't we do that?"

Allison's eyes had gone wide. "Are you suggesting a threesome?!" When Isaac just shrugged, she turned to Scott for backup. "Scott, tell him he's crazy."

While Scott had certainly been stunned by this turn of events, he couldn't pretend he wasn't intrigued by the idea, though he hadn't really thought about being with a guy before. Much. "Maybe … not so crazy."

Allison couldn't believe what she was hearing. "And you two … would be okay with that?"

"I'd be more than okay with it," Isaac said. But instead of going for her, he'd kissed Scott instead. Everything after that really was a blur. At one point they all climbed into Scott's bed where they became a mess of tangled bodies. It was incredible. And even after the fun, when they all just laid together feeling utterly spent and satisfied, that had been nice too. At least until Stiles had come running into Scott's room, ruining the moment and forcing them to come crashing back to reality.

Isaac looked between them now. He wasn't going to pretend this wasn't an outcome he'd always hoped for. "You're right, I did start it that night. And I'd do it again. Allison, you love both of us, right?"

"Yes," she said without hesitation.

"And I love you, and I love Scott," Isaac said. He turned to Scott. "So why can't this work?"

Scott finally stopped staring at his feet. "Are you sure you're not mixing up your feelings for me now that I'm your Alpha? Because those are some really strong feelings of loyalty and maybe –"

Isaac bridged the gap between them and stopped him with a kiss. Scott kissed him back. When they broke apart, Isaac said, "I'm sure."

Allison went over to them and took their hands. She teased Scott, "And let's not pretend like there weren't moments where I wasn't involved at all."

Scott could feel himself blushing, and he bit his lip to keep himself from smiling. He looked between them and couldn't keep the awe out of his voice when he said, "Are we really doing this?"

Allison and Isaac smiled at each other, and then looked back at Scott. Allison said, "I think we are."

It didn't take long for the clothes to start coming off.

Several minutes later, Stiles and Malia were still sitting outside the door. Stiles turned to Malia. "It's been quiet in there for a while now. Do you hear anything?"

Malia listened closely. "Uh … Stiles? I'm almost positive they're having sex in there."

"WHAT?!"