I have a challenge for anyone who wants it. A man's wife has been murdered three years ago by a vampire. The vampire leaves town only to return for insert reason here. The man finds out that the vampire in question is back and goes out seeking revenge for his wife's death. The man in question is about 80 and can't fight. In fact he's in a wheel chair but he wants to avenge his wife's death. In a suicide mission the man goes into the vampire's nast with crosses around his neck and wooden stake's strapped on the arms of his chair. Buffy stumbles on the sceen and saves the man only to have the vampire get away. The man is pissed about being saved and curses the Slayer for saving him. Buffy a wheels the man back home and the man tells her the story of how is wife died. By the time she gets the man back home Buffy wants to help the man avange his wife. The old man's only request is that he is there when Buffy kills the vampire. Everynight she goes out with this man to find this vampire and he fills the time by telling her stories about his wife and how they met.
Somehow Spike gets involve maybe he's already doing the whole stalking thing or maybe Buffy tries to pump him for information. Either way Spike starts joining them on the hunt listening to this old man's love story and his relentless need for revenge.

Set in either Season 3, 4, 5, or 6.
The story of the old man's wife must mirror Buffy and Spike's own story minus the supernatural elements.
The old man must also tell off both Buffy and Spike about there long lost love affairs
The old man has to die after his wife is avenged
Happy Spuffy ending