Stage Zero: Vampire Takeover
(begins with your founding couple)
It began several months ago; when the vampires announced their presence to the world through popular media. People were wary, careful at night, they didn't know who could be trusted.
And then the attacks started: a human killed a vampire using the excuse that they thought it was attacking them. Law enforcement allowed it to slide. It happened again and again. The vampires got mad. The vampires decided that their food source had to be made compliant or die.
So they began picking people off, shipping them to contained towns out of the cities, away from the population. You and your partner got away, ran as far as you could. You've sequestered yourselves behind an electric fence in a safe house you'd heard about.
Somehow they've done something to the sun. It is always night time now. You're lucky the greenhouse has UV lights, but with those and the fence you can't use anything else.
Everyone around you is a Vampire. Literally. You managed to survive due to the traits you picked up along the way. Now you have to keep surviving.