Vampires are real and they hunt at comic conventions.
And why wouldn't they? It's perfect. They're huge, windowless rooms full of weak, pasty, loners who wouldn't be missed if they disappeared. Some of them are so horny for vampire slash fic they'll willingly give themselves to the vampires. The bloodsuckers can even walk around in their true forms with impunity -- some have even won awards for their "cosplay."
"Father" Todd Lincoln, AKA Linc, is a grifter who sells crappy weapons at comic conventions. His schtick is that he 'blesses' the weapons: guaranteed to slay the undead or your money back! What Linc doesn't know, though, is that not only are the undead very, very real, they're also very, very pissed off that these blessed weapons actually kill them.
Linc, finding himself targeted by the vamps, joins up with Warner Wesley and Belladonna Noir, vampire hunter drifters with chips on their shoulders. With no choice but to team up to survive, Linc soon finds himself in the world of the bloodsuckers, who've been operating behind the scene for nearly all of history.