This story takes place about one hundred years ago. Nadja is a bright, cheerful girl who was raised in an orphanage near London, England. Nadja was entrusted to the orphanage when she was a baby. So she thought her father and mother were dead. But before her thirteenth birthday, she found out that her mother might be alive.. Nadja sets out on a journey to find her mother! With all of Europe as the stage, Nadja's exciting adventure begins!

Sonnet is a cyborg/esper from a harsh background and now trained to be the ultimate warrior and most powerful weapon in the world. She is sent to Japan to watch Komatsuzaki Lan, who is thought to be controlled by the rage of the esper Akai Kiba (Crimson Fang). Lan is a quiet girl who knows she's different from everybody else and starts to show signs of Crimson Fang after coming into contact with Sonnet. In the course of fighting with Lan, Sonnet starts to rediscover her humanity. At the same time Lan has to fight to retain her humanity and control the Crimson Fang.

At the behest of her father, Yui Komori goes to live in a secluded mansion, home to the six Sakamaki brothers—Shuu, Reiji, Ayato, Kanato, Laito, and Subaru—a family of vampires. Though at first the siblings are confused as to why the girl has arrived, they soon realize that she is to be their new "sacrificial bride," not to mention their other, more carnal intentions for her. After meeting the brothers, Yui quickly begins to question why her father would have sent her here and why she feels a strange, new pain in her chest. With each brother more sadistic than the last, Yui's life as a captive takes a harrowing turn in her new home. As her days turn into endless nights, and each brother vows to make her his own, Yui falls deeper and deeper into madness and ecstasy.

Yui Komori, still held captive by the Sakamaki brothers—pureblood vampires after her blood—experiences yet more bizarre twists to her life following her stay at their household. Though haunted by enigmatic dreams, Yui soon deciphers their meaning when caught in a car crash, which subsequently leads to meeting four new vampires: the Mukami brothers, Ruki, Azusa, Kou, and Yuuma, who themselves capture the bewildered girl. Yui later awakens in the Mukami mansion, where the brothers reveal their plans for her: she is their "Eve," and her blood will find the "Adam" among them; together, they will have the power to rule the world. However, with the Sakamaki brothers hot on their heels, things might not go quite as smoothly as they had imagined.