Its the summer between his freshman and sophomore year when his stepdad crashes their car into tree so hard it splits the vehicle in half. They're out in the back country at the time, miles from the main road and any traffic. They're out there for hours. Kidd lost consciousness on impact, and didn't wake up again until he was stable in the hospital. His stepdad never came off the mountain alive. The how and why never get mention to him - everyone's more worried about him getting better. Healing. Dealing with the fact his left arm was severed just above the elbow and there was nothing the docs could do but close it up.
Killer's truck is stained with his blood for the rest of the summer, until he can finally afford to replace the bench. He won't let Kidd in his truck until he does. That's how Kidd finds out Killer was the one to find them, pulled Kidd out of the wreck and used his own belt to tourniquet Kidd's arm to keep him from bleeding out. That he's the one to drive Kidd down off the mountain that day.
Kidd feels like he owes Killer his life; Killer feels like it's his fault Kidd lost his arm.
