Blameless by Gail Carriger AU.

Stiles spent the night at the police station. He had been shot at. Shot at. Not that he wasn't used to death threats, but he had never been shot at. His father was the police commissioner and he was married to the area's Alpha werewolf who was also a federal agent. People didn't shoot at him. Even if said husband was pissed at him for reasons Stiles couldn't fathom.

Or well, the reasons had something to do with the small child sitting next to him at the police station. It was a young boy with dark hair, nearly black, and starling green eyes. Stiles would almost say he looked like Derek, except the boy's features were softer somehow. Stiles had asked him name, but the boy said he didn't have one.

Stiles had left his home with the child, or more accurately, been thrown out of it, when Derek had started snarling at him and the boy. Stiles was fairly certain Derek had been insinuating that Stiles had slept with his sister and this boy was the result. Stiles wasn't even aware that Derek had a sister that was alive, nor had he slept with anyone since long before dating Derek, which meant there was no way the two year old by his side could be his child. Hell, he'd been married to Derek for over a year and they'd been together for two years before that. It had been ages since he'd been with someone besides Derek.

Stiles got a text from Laura Hale. "Come quickly. I need to speak to you immediately." Stiles tried to answer that he was currently sitting in the police station and might be awhile, but Laura never replied.

Instead, Stiles opened the envelope that Derek's Beta, Chris Argent, had shoved in his hand when Stiles had arrived back at Newark Castle and its surprise toddler.

Stiles,

I never got a chance to apologize for all of that business with Blake. I've been following your research since then and it is intriguing. I look forward to more in the future. I have been helping BUR take down some of the more radical branches of the Order of Oborous. That was the scientific society Blake belonged to. I'm not sure if you were ever made aware of that. The order itself is fine, but there have been offshoots that are using more and more illegal activity to study supernaturals. One I'm working with now was keeping this boy. I snuck a look at his files and it listed "Z.S. – effervescent" as the father and "L.H. – vampire" as the mother. You are the only preternatural I've heard of, so I figured he must be yours. Maybe you know the mother? I'm still undercover, so I had to sneak him away, but I left him under the care of Agent Chris Argent with BUR. I didn't explain anything, but just asked him to give you this note. I didn't want to create any problems between you and Agent Hale. I wasn't sure what else to do, but after seeing what some of these offshoots were willing to do, I couldn't leave a child there. I know he will be safe with you as a father.

Regards,

Danny M.

Stiles stared at the letter for a long while. Not that he could trust the files or Danny's report of them, necessarily, but there could be no doubt the effervescent listed was him. His first name was not commonly known and how many other preternaturals could have the initials Z.S., particularly since Stiles was the only effervescent in the country? And Blake and her men had kept both he and Laura unconscious for a long while when they had been kidnapped over three years ago. There was no telling what they had done to Stiles at that time.

And, oh god, Laura, thought Stiles. L.H.? Could it be?

Stiles had spent the better part of the past three years trying to determine if there was any connection between Derek and Laura other than a shared last name. They shared some similar looks, but other than that, did not seem to interact outside of official business.

But then, Stiles thought, Laura did look an awful lot like Cora, the only relative of Derek's that Stiles knew. Was this why Derek thought Stiles had slept with his sister? Because Laura was his sister? If anyone could turn a vampire mortal, it would be Stiles. Although how could anyone keep Laura mortal long enough for her to be pregnant, give birth, and hide it, Stiles wondered. Especially without Derek noticing. And how could this child be his and Laura's? They'd never slept together. They'd never even wanted to sleep together.

Stiles had so many questions and nobody to answer them.

He had tried calling Derek's phone twice with no answer. He called Argent, but was told very sharply, "This is not the time, Stiles," and was hung up on. Derek was not going to listen to him, it seemed. Stiles was torn between hurt and anger.

Stiles's father finally came up to the front of the station.

"They're letting you go for now. They've got your statement and they want to know if you find out anything else. Right now, they're treating it as either a threat to me or Derek. They'll be passing along any information to BUR."

Stiles nodded sullenly. Of course they would. Maybe Derek would care that someone was trying to kill him. Maybe.

"Son, come stay with me tonight. Bring the boy. I don't know what you've gotten yourself into, but you know I'm always here."

Stiles smiled slightly at his dad. It wasn't like he had anywhere else to go.

John Stilinski. "I'm calling Finstock tomorrow, too. Especially if Derek isn't going to put any BUR agents on you. I don't want you alone."

"What if he's busy? Going to keep me on house arrest?" Stiles had devolved into a petulant teenager, he was pretty sure. Something about being ordered around by his father did that to him.

John rolled his eyes. "He's never busy. When you were younger someone threatened me. They said they'd take you to get to me. Finstock told me he promised your mother he'd always protect you and he'd come play bodyguard whenever I needed it."

"Is that the two weeks he was over when I was 8? He made me watch Independence Day nonstop. I still have the speech memorized."

John chuckled. "Yea. Glad he didn't let on what was actually happening, at any rate. Now I can't seem to keep you out of any messes. Hell, half the time you're the one making them."

They walked to John's car. Stiles's was being kept for evidence, as it had a bullet hole through the front windshield. They rode back to Stiles's father's place in silence.

When they arrived, Finstock was already on the porch.

"I thought you were going to call him tomorrow," Stiles said accusingly.

"I was," John replied.

"Stilinski! Get the boy inside, quickly!" Finstock's frantic voice sounded loud in the quiet neighborhood. He wasn't looking at Stiles though. He was looking at the boy that accompanied him.

Finstock shuffled the boy into the house, scanning the street for anyone who wasn't supposed to be there.

"That attempt wasn't on you, Stiles. They were trying for the boy."

"What?" Stiles was shocked. Who would want to kill a two year old? "Why?"

Finstock shrugged, but didn't say anything. John gave him a look, but didn't ask any anything. He shook his head at Stiles when he made to ask more questions.

"Not right now, Stiles."

Stiles's father never kept secrets from him. He couldn't fathom why he was keeping them about threats to a child – a child that might possibly be Stiles's son (although he still wasn't too sure about that – mostly because he couldn't figure out how), but he let it go. Neither his dad nor Finstock looked like they were going to give on the subject that night.

As Stiles was settling in to sleep, he realized he never went to Laura's after she texted. He wondered if whatever she needed him for had anything to do with the boy. He decided to go see her first thing in the morning.

The next morning, though, he arrived at Laura's to find it empty. Not just empty, but abandonded.