This city fantasy starts with a legend. There was a virgin in ancient Byzantium who became cursed. Wherever she went, bad things were sure to follow. The curse opened a vortex of damnation around her and the first forces of darkness were born into the world. Forces of light rose to fight them. Geser (Vladimir Menshov) is the boss of the forces of light and Zavulon (Viktor Verzhbitski) is the general of the dark forces.
The battle that raged was bloody and violent and the forces were so equally matched that a truce had to be negotiated unless everyone was to perish. The truce basically says no one gets to pick a fight and each person has to choose for themselves if they go to the light or dark side. And that is what it all comes down to, really — choice.
The protagonist Anton (Konstantin Khabenskiy) goes to a woman who he believes to be a witch of sorts in order to get his philandering wife back. She tells him that his wife is with another man, carrying this other man’s child, and offers to make the child go away and the wife come back, if Anton is willing to take the sin on his own conscience. Anton doesn’t really seem to understand how serious this is, so he says yes. The problem is that the woman, Darya (Rimma Markova), is the real deal. She is an Other, a Dark Other, even, and she actually can make all this come to pass.
At the exact moment the curse is about to take effect the Night Watch show up, traveling in the Gloom, the other dimension, where they are supposed to be invisible to regular humans. The problem is that Anton can see them. They restrain the witch and once they realize that Anton can see them they take him in.
Next time we meet Anton he is drinking blood and hunting vampires who have broken their particular set of laws. Vampires need licenses to be allowed to bite humans and Anton, who is a seer, is hunting one that has gotten in over his head.