Victor Decimus is a 2,000 year old vampire, having last seen the sun when he was a Roman soldier in biblical times. There are few rules that govern a vampire's existence, but those rules are absolute: 1) Vampires are not allowed to associate with other vampires and 2) Once a vampire convinces a human to take his place as a vampire, he must leave the earthly realm for the Dark Kingdom. Victor, unfortunately, has broken both those rules - he's sired his human lover Paul as a vampire and stayed with him on Earth.
The two enjoy an intense life as lovers, living in Georgetown and mingling at their private club for devotees, a converted church now known as Dies Irae. But their transgression is not taken lightly and agents for the Dark Realm are now on the prowl, looking to enforce their will and, if necessary, threaten everything that Victor and Paul hold dear, even each other, to punish their transgression.