All I remember is that Xander has visions, or can see the future, he's at a bar trying to drink it away when he has a vision about Spike. He saves Spike. Spike asks him about it and he lies that he saw the reflection in the mirror. Spike figures it out eventually though and keeps tagging along to prove that Xander can see the future even though it keeps denying it.
Some one please help me find this fic!