Season 1

Vampire Jirou and his brother Kotarou set sail to Yokohama. Kotarou being a restless kid starts wondering around the boat and stumbles upon a fight between the suppression team, and the vampires. Jirou comes to stop the racket, but a grenade knocked Kotarou off board. Jirou dives after him but due to his blood, water injures him.

Jirou survives the water and bring his brother to the beach as a skeleton. They then meet a compromiser named Mimiko, who promises to take them to the special zone. Wong then appears and request that Jirou would join her, but then the suppression team arrives and shoot’s Wong in the shoulder. Jirou escapes with Kotarou and Mimiko, but then leaves to distract the suppression team as his brother escapes.

Ordinarily, humans won't evolve unless they drink the blood of a black blood. However, they can change humans by sucking their blood and turn theam into the same bloodline as the black blood. If they ignore that existance, the world will be ruined.

Jirou is still trying to get Katarou, but he is weak. Will he be able to save Katarou in time and destroy the kowloon child?

The place where Mimi works at finds out about her assisting Jirou, so she leaves and tries to find Jirou and Katarou a place to stay at. But during this they get attacked by some vampires. Will Jirou be able to beat them and protect Katarou and Mimi? Or will he perish in the attempt?

Jirou learns about the order of criminals called Kabun, led by an old acquaintance of Jirou called Zelman. What will happen when Zelman and Jirou meet?

After the explosion, Jirou leaves to take revenge. But Ogius seems to be a kowloon child now. What will happen to Jirou? Will he survive? Will he win the battle?

Jirou decides he wants to leave the special zone after he learns that Cassa is there, but then Katarou leaves, leaving a note behind and Jirou can't seem to find him anywhere. What could have happened to Katarou? Does Cassa have him? Will Jirou ever find him?

Katarou and Zelman go off looking for Mimiko, meanwhile Mimiko goes off to the place of the eleventh yard expert. And Jirou is trying to find out what Cassa is doing in the special zone. Can Katarou and Zelman find Mimiko? Can Mimiko find out about this eleventh yard? And can Jirou find out what Cassa wants with the special zone?

Mimiko finds out that she is actually with Cassa and not Wong. Then Katarou and Zelman show up to her rescue, but unluckily she escapes, then they find out that blood bags with the kowloon blood have been scattered all over the special zone. Now there is an infestation of the Kowloon children. Can they be stopped?

Sei was put down the barrier protecting the special zone and is helping to destroy the kowloon children. Jirou meets up with Katarou and Mimiko, and is able to convince him. But right there Walkerman comes and fights Jirou, but Jirou is weak now. Will he win the fight? Will he stay in the special zone?

Jirou defeats Cassa, and later on finds out that in the eleventh yard lies the remains of the kowloon king. Then he is told to be Mimiko's guardian. A bit after Jirou tells Mimiko to not tell Kotarou abiout him being the reincarnation of the sage, Eve. Jirou seems to have gotten a job, and they all live happily ever after!