A/n this is before Derek and stiles are together, set in season 3A. Derek knows that he and stiles are mates but stiles doesn't know yet, which is why he told Scott not to tell stiles where he was going so stiles can move on if he dies.
Derek's pov
I went to kill Deucalion, at an abandoned warehouse in the middle of beacon hills. I didn't tell anyone I was going except Scott and I warned him not to tell stiles where I was going. Scott asked me not to go.. To just stay and tell stiles what was going on but I couldn't bare it, if I died stiles would never know we were mates meaning he didn't have to grieve over me and he could find someone else. As I got to the building alone I realised he wasn't and I had to take on 3 alphas by myself I remember Scott showing up to help me stiles in tow as I was threw off the second floor with one of the alphas on me as well so we both fell, I saw the worry in Scott and stiles' eyes when we fell I was scared both me and the other alpha let go of each other falling on escalators that were in the building each falling on a different escalator.
Stiles' pov
*a week later*
I'm outside of Derek's loft I don't know why I'm there I just ended up there, there was no movement at all in the whole building... "I can't believe you're dead" I whispered to myself, it was raining and I was crying the love of my life was dead and I didn't tell him how I felt when I should've I've been dreaming about him all week and having hallucinations that's he's there and talking to me when he's not, that's when I heard his voice behind me. "Stiles?" The voice said "no!, no? You're not there you died" "turn around stiles"the voice said again "I can't unless you're really there I can't live without you Derek we save each other and I couldn't save you so promise me you'll really be there if I turn around" "I promise sti"he said again. I slowly turned around letting the tears flow as I expected the worst I wanted him to be there so badly I closed my eyes not letting my mind fool me again "look at me sti?" I slowly opened my eyes to actually see Derek standing there soaking from the rain like myself. I just ran into his arms hugging him as tight as I could, he hugged me back "never EVER do that to me ever again Derek! I thought you were dead!" I loosened my grip standing back for a minute before crashing my lips into his, once the kiss had finished I looked at the floor and said "sorry, I shouldn't have done that I don't regret it but I know you don't like me like that" Derek then smiled pulling my chin up with his hand making me look at him and then he said "you couldn't be more wrong" then he kissed me again and I kissed back passionately "you're never leaving me again you know that don't you?" I said in kind of a squeak "I never want to" Derek replied and we stood there holding each other in the rainy night until we finally went in to Derek's loft passing out on his bed, entwined together.
A/n hope you like this still taking requests if anyone wants anything for Sterek please ask, slowly running out of things to write. Thank you.