After his father's passing, Yuuki becomes accustomed to his solitary life until a peculiar girl named Mikage enters his world, making herself at home in his residence. Unbeknownst to him, Mikage is a unique breed of vampire, diverging from common folklore as she can endure sunlight and sustains herself on more than just blood. Yuuki, who harbors antibodies against vampiric transformation, finds himself entwined in a cohabitation with Mikage. However, this arrangement triggers heightened bouts of his carnal desires, thanks to his unique immune response to vampires. The situation escalates when Yuuki discovers the existence of other vampires beyond Mikage, complicating his already tumultuous life.