The night watch - Sergei Lukianenko

Walking the streets of Moscow, indistinguishable from the rest of its population, are the Others. Possessors of supernatural powers and capable of entering the Twilight, a shadowy parallel world existing in parallel to our own, each Other owes allegiance either to the Dark or the Light.

The Night Watch, first book in the Night Watch series, follows Anton, a young Other owing allegiance to the Light. As a Night Watch agent he must patrol the streets and metro of the city, protecting ordinary people from the vampires and magicians of the Dark. When he comes across Svetlana, a young woman under a powerful curse, and saves an unfledged Other, Egor, from vampires, he becomes involved in events that threaten the uneasy truce, and the whole city...