It's a funny thing, losing a loved one. It's like walking up to your room in the dark and thinking there's one more stair than there is. Your foot falls through the air and there's a sickly moment of dark surprise.
Stiles knows that feeling well. He's been taking that extra step since he was eight years old and he felt his mother's hand grow cold in his little ones. His dad tried to be there to catch him, but sometimes he was out working late or trying to catch his own fall in the bottom of a bottle. Stiles has learnt to be more steady on his feet. He still stumbles sometimes.
Derek knows that feeling more than he ever got to know his sisters. For him, it's more like the entire staircase was burnt to the ground in a flare of flame, choking him with smoke and ash, but every night he tries to climb it. And every night he falls. Laura used to catch him some nights. Now she's yet another phantom step for him to trip up. Another piece missing.
Together, though, together Derek and Stiles help each other. Underneath the cutting comments and the barbed words, under the playful shoves and the threats and all of their obvious-to-everyone-but-each-other attraction to one another, they're the same. Despite the fact that Stiles can talk a mile a minute and Derek sometimes goes days without a word. Despite the fact that Stiles can barely stop moving long enough to fall asleep and Derek finds solace in stillness. Despite the fact that Stiles is practically made of smiles and Derek hardly remembers how any more. Despite all that, their souls are made of the same stuff – two halves of a whole. Both broken, both beautiful, both strong and smart and stubborn as hell.
It takes them months to realise that underneath the I hate you is something much more akin to I love you. Not quite that yet, but maybe I care about you or I need you to be safe. Something along those lines. Something that smells of pack and home and something nameless that Derek wants to burrow his nose into and breathe. Something that cuts through the skittering of Stiles' mind, that's sure and strong and allows him to open up his lungs and breathe.
The pack cheer when they finally get together, Isaac smirking as Boyd grumbles and hands him a crumpled $20 note, Erica shooting them a feral grin and asking who'll top, Scott manfully trying not to cry and Allison shoving him in the shoulder. Lydia just gives a knowing smile and Jackson rolls his eyes, but he's smiling too. Cora doesn't even try to hide the fat tears rolling down her cheeks. She and Scott share a look – they're happy it says, it's been so long. Stiles and Derek close their eyes and block them out, content to breathe each other in.