Vampires live in civilization as part of its underbelly. They do not need blood to survive, but intense emotions may greatly enhance their bloodlust, transforming them into uncontrollable monsters. Tsukasa Taira, a 22-year-old university student, discovers the existence of vampires following a stressful confrontation with Yuuki Anzai, a human and vampire hybrid. When her buddy is arrested, Tsukasa is pulled to Anzai, who unwillingly reciprocates her affections. This unorthodox romance, however, may be too tough to sustain, as Anzai battles to suppress the part of him that wants to devour Tsukasa.