On live television, Mina Tepes, the ruler of all vampires, reveals the existence of her species to the world and states her plan to build a sanctuary in Japan for vampires, called the Vampire Bund. Using her family's wealth to pay off the nation's debt, they have agreed to let her build this safe-haven for her fellow creatures of the night. But not everyone is so easily swayed by Mina's influence, as her announcement brings about conflict with humans who believe that the queen's quest for peace is a façade. Akira Kaburagi does not believe in vampires and gets uneasy whenever they are brought up, although he has yet to realize why. Apart from suffering a head injury a year ago, he lives on blissfully until he meets Mina. She triggers within him memories of a life he had long forgotten, and he soon begins protecting her without understanding why. But Akira's secret is far stranger than he could have ever thought possible—he discovers that he is a werewolf, sworn from birth to protect the vampire queen, even if it costs him his life. Now, as these two dance a rondo of death in the Vampire Bund, Mina and Akira find out just how deep their bond goes.

The ability to create miracles is not just a supernatural phenomenon; it is a gift which manifests in a limited number of human beings. "Minimum," or small miracles, are special powers that only selected people called "Minimum Holders" possess. The detective agency Yokohama Troubleshooting, or Hamatora for short, is composed of the "Minimum Holder PI Duo," Nice and Murasaki. Their office is a lone table at Cafe Nowhere, where the pair and their coworkers await new clients. Suddenly, the jobs that they begin to receive seem to have strange connections to the serial killer whom their friend Art, a police officer, is searching for. The murder victims share a single similarity: they are all Minimum Holders. Nice and Murasaki, as holders themselves, are drawn to the case—but what exactly is the link between Nice and the one who orchestrates it all? [Written by MAL Rewrite]

The story revolves around D, the infamous "dhampir" (born of a vampire father and a human mother) outcast and renowned vampire hunter. His prowess at hunting the creatures of the night allowing his acceptance among humans, he is called upon to locate Charlotte Elbourne, the lovely daughter of an affluent family who has been mysteriously kidnapped. When the sun sets, the hunt goes on! Charlotte's father offers a rich bounty, be she dead or alive, a task D willingly accepts, even with notorious Markus brothers and their gang of bounty hunters seeking the prize as well. Amidst the chase and unknown to all lurks, a sinister evil which has been secretly manipulating their every move and has set a chilling trap that none will expect and few will survive. With the tables turned and the secrets revealed, the hunters could quickly become the hunted! (Source: AniDB)

The anime follows a salaryman who has a chance meeting with a girl named Ai on the train. They begin to meet every Monday on the train, with the man serving as her bodyguard on the crowded commute while they chat. (Source: ANN)