Valeria Costacurta, a 16-year old girl from a formerly prestigious noble family, has been chosen to become a Dominas due to possession of a crest. Only those who possess a crest tattooed on their body are able to wield magic, and due to the low odds of possessing a crest (roughly one in ten), Valeria accepted her role as a Dominas in order to revive her family's noble status. She wants to achieve this with her own strength as her lifelong dream, and to her, the first step to accomplishing this dream just came her way with the appearance of her own crest.
While every other Dominas, being maidens, are paired off with female partners (called Hiera-Glaphicos) in order to protect their purity, in her case, Valeria's Hiera-Glaphicos is the young man known as Dimitar Richternach. He comes off as foul-mouthed, brash and tactless according to Valeria; Valeria, on the other hand, is viewed by Dimitar as haughty, overbearing, and completely clueless about the world. Dimitar's aunt, Orvieto Richternach, assures Valeria that he will never lay a hand on her—because Dimitar only has eyes for older women.
Their adventures begin when their first assignment is a secret mission—to investigate a supposed rebellious uprising in a nearby city, except things don't go as they were supposed to, and a simple scouting mission quickly turns sour.