Poison for the Moon, Medicine for the Night

It has been more than a hundred years since the world was sealed in night.
Niko leads a double life: apothecary by trade, assassin by contract. One night, she catches a girl falling from the sky.
Silver hair, ruby eyes—the girl sinks her fangs into Niko's throat and murmurs, "I'm hungry." Her name is Lamica Alu-card, princess of the vampires, a race that harbors the night itself within them.
Soon after, Niko receives her next order: assassinate the vampire princess.
An assassin who longs for death and a princess marked for death. Sweet as poison, warm as medicine, their story begins.

Source: Dokico