When out on patrol one night, Buffy encounters two strange men who she thinks are vampires. We known these men as Sam and Dean. (Note: This takes place sometime after season seven in Buffy, in a version where Spike has a soul, but gang never encountered The First Evil, and as a stand-alone episode sometime during season five for Supernatural.) Sam stops Dean before he can shoot Buffy, but not before Buffy puts a stake in Sam's gut. Devastated to realize Dan's a human, Buffy brings the pair back to Giles' House for some R&amp;R. While Dean's recovering Sam and the Scooby Gang do some research to find out how Sam and Dean landed in Sunnydale, which is a completely different dimension! What they discover is that Sam and Dean crossed over during a Double Blue Harvest Moon. The moon disappears a week from now, same time, same place. If Sam and Dean don't leave by then, reality will be forced to repair itself, creating untold consequences. Problem is, Sam and Buffy are falling for each other. Which makes it even more interesting when Spike shows up. Some one get the stakes!