An organization called Chronos governs in the shadows much of the political and economic activities in search of order. Its members killed without mercy everything that goes wrong or opposes them. The opening theme "Daia no Hana" by Yoriko. The first ending theme "Namidaboshi" was performed by PUPPYPET.
The story begins when Train, known as Black Cat (Black Cat), one of the most powerful murderers organization, meets a strange woman named Saya Minatsuki, who always wears a kimono striking and softens his heart. She decides not to take orders from anyone or kill without reason. Saya is killed by Creed, who calls her a witch, then made Train stop being a murderer.