Thousands of years ago, Vampire King Akabara Rosered Strauss lost both his kingdom and his queen. Since humans were unable to kill the queen, they sealed her away, erecting thousands of fake seals so that the king would never find her true location. Despite being pursued by relentless hampires, Akabara continues to search for his queen to this day. Akabara’s quest takes a sinister turn when an entity called the Black Swan appears. The Black Swan inhabits the body of a young human girl every 50 years, giving her the power to destroy the Vampire King and his queen. With each incarnation the Black Swan grows stronger–will the 49th Black Swan mean the end of Akabara?

Kiyotaka Narumi, a world-class detective, has been missing for two years. His last words prior to his mysterious disappearance were “I’m going to uncover the mystery of the Blade Children.” These words have haunted Kiyotaka’s younger brother Ayumu ever since, but neither he nor anyone else has gotten any closer to figuring out their meaning. But after Ayumu becomes the prime suspect in a murder, he begins to discover people with links to the ‘Blade Children’ all around him! Following in his brother’s footsteps, Ayumu now must begin his own investigation into the mysterious Blade Children…