Ten years after the Holy War in Hong Kong, Mochizuki Jirou, aka the Silver Blade, and the lone hero who fought and defeated the Kowloon Children despite the loss of his lover, returns to Japan with his young brother, Mochizuki Kotarou. The two quickly discover that the Kowloon Children who survived the Holy War are seeking to infiltrate the "Special Zone", a thriving city protected by an invisible barrier that will not allow Kowloon Children entrance, unless they're invited. Red Bloods refers to the humans; Black Bloods are the vampires, and the Mochizuki Brothers are Old Blood, the last descendants of an elite clan of vampires. When Kotarou is abducted by one of the Kowloon Children, Jirou has no choice but to fight once more.

The world is divided into two kingdoms: the Kingdom of White, which floats in the heavens and is ruled by their queen Iris, and the Kingdom of Black, which stands upon desolate land below and houses the King of Darkness as its ruler. As of late, forces of evil have amassed great power, posing a threat to the entire world. Being the main representative of the Light, it is Iris' duty to maintain the balance of the world and fight off the darkness in her kingdom. Meanwhile in the Kingdom of Black, rampaging monsters annihilate a certain boy's village, leaving him the sole survivor. As he grieves in hopelessness, an armored man named Skeer notices the child and comforts him. Soon after, Skeer recognizes the boy's potential to change the kingdom's status quo and makes him his heir before passing away. The boy then vows to become the Prince of Darkness—the one who will replace the King—to bring the world back to its rightful path. As Iris and Prince of Darkness each challenge the impending doom the world faces in their own respective ways, their destinies will converge with each other, and perhaps, their bond will decide the fate of the world. [Written by MAL Rewrite]

Following the events of Jigoku Shoujo Futakomori, Ai Enma, the Hell Girl, has disappeared. Her former companions decide to lead normal lives, until their absent mistress returns to them with a new companion, and in a way that none of them anticipated. Yuzuki Mikage is a normal schoolgirl who soon comes to understand the Hell Girl on an intimate level. During a dream-like trance in the bathtub, Ai kisses Yuzuki and possesses her. So when Yuzuki's friend decides to type in the name of their teacher in the Hell Correspondence website, Ai makes use of Yuzuki's body to accomplish her own task of ferrying the teacher's soul to hell. Yuzuki is disturbed by her new circumstances and wonders why she was chosen to continue Ai's work. Unfortunately for her, the Hell Girl and her assistants resume operation of Hell Correspondence, and she is dragged along for the ride towards hell itself. [Written by MAL Rewrite]

Specials included with the BD/DVD release of Kobayashi-san Chi no Maid Dragon.