It's been four months since the night of the final battle: the night Stiles and Derek first kissed. They've been basically inseparable, especially now, since graduation has come and gone. It's the middle of June and Derek and Stiles are staring at the ceiling of Derek's bedroom. Stiles announces "I think I love you" and gets a response he definitely wasn't expecting.

"Think?" Derek growls and leaps out of the bed.

"Hey, what's the problem? I just said that I loved you." Stiles is hurt and confused.

"You 'think'," Derek forces out through clenched fangs.

"Yeah, I think. But I'm really not sure after the way you're acting now!" Stiles is really starting to get mad. "You're being a jerk. I thought you'd be happy."

Derek lets his eyes glow bright and allows a furious growl to escape his throat. He nearly rips the door off its hinges as he swings it open. He charges out and leaps down the newly renovated staircase. He storms through the kitchen and growls a warning before anyone can ask him what's wrong. He stalks out the kitchen door and leaves his pack wondering what on earth happened.

Stiles trips down the stairs while trying to pull his pants on. There's a look of confused shock on his face.

"What did you say to him?" Scott asks with wide eyes.

"Really, you're taking his side?" Stiles questions. He runs his hands over his head. "I didn't say anything. All I…" Stiles trails off as his hurt feelings rise back up. Why would Derek act that way?

"What is it?" Lydia asks.

"I said I thought I was in love with him."

"You 'thought'?" Scott stutters out.

"Yes, thought, think… What's the problem with that word? That's what he said."

"Dude, you seriously shoved your foot in your mouth." Scott says, shaking his head.

Stiles stares at him, not understanding anything and wishing he hadn't even woken up this morning.

"Like, you literally shoved your foot in your mouth, swallowed it, cr…"

Allison elbows Scott in the ribs.

"What is going on?!" Stiles is utterly confused.

Jackson is the one to answer. "Stilinksi, you're Derek's mate. You basically just broke his heart because he already loves you with every ounce of his being."

Everyone stares at him incredulously.

"What?" he hisses.

"I'm his mate? Is that why…" As if in a trance, Stiles walks through the kitchen, out the door, and into the woods behind the house.

He finds Derek sitting on a log. He's shaking with utter rage. Stiles reaches out to him and doesn't even flinch when Derek jerks his face around to growl at him. He sits down and holds Derek's face in his hands.

"Really poor choice of words back there." Stiles swallows and sighs as Derek's features refuse to change. He pulls him in for a kiss. "I totally love you."

"They told you," Derek huffs.

"About the whole mate thing? Yeah."

"I wanted you to choose me completely because you wanted to be with me. Not because you knew I was mated to you."

"I knew I wanted to spend the rest of my life with you long before now. You do realize I was the one who kissed you first."

"When?"

"Four months ago."

Derek whines at Stiles' snarky humor. "When did you know?"

"When me and Scott saw you in the woods. When you saved me from Peter. When I held you up in the pool for two hours. When you stopped Jackson from ripping my dad apart. When I dented your Camaro and you didn't rip my throat out with your teeth. When you didn't laugh when I told you my first name. When I broke my ankle and you took me to the hospital because even though I was unconscious, I know it was you. When we first kissed and you wanted to bolt, but you stayed. Every time is the first time I know I love you, want to be with you because… I've always known yet never known all at the same time, because I'm an idiot and can't sort out my feelings. I'm basically as emotionally constipated as you are, Mr. Sourwolf. And if you don't believe me, or just can't understand what I'm trying to say, because, believe me, I've confused myself, too, just listen to my heart because you can hear that I'm telling the truth." Stiles gasps air, sweet sweet air, into his burning lungs. As oxygen rushes back to his brain, he realizes Derek looks human again.

Derek pulls him in and kisses him passionately. They stay there in the woods all day long. It isn't until the stars are out that they come back to the house, drenched with each other's sweat and coated in dirt.