Okay, guys, for the life of me I can't remember which fic this is and it's been bugging me since I've been wanting to read it again. All I remember about it is one scene in particular. Spike's in a vamp coma for some reason, I think he'd been beaten pretty badly, and Xander is the one taking care of him. When Xander's dad comes home, Xander hides Spike in his closet on top of some pillows and promises that he won't let his dad get anywhere near Spike. The whole time Xander's dad is beating him (I don't remember if he rapes him or not, I just know that it's a possibility since there was definite H/C going on later), Spike can hear and smell everything. After his dad leaves, Xander just has enough strength to get to the closet and he passes out in there against Spike, who vows to protect him from then on.