The Solitary Cat.Train Heartnet, an assassin known as the Black Cat, and a sweeper named Sven Vollfied pursue the same target without realizing it, the feared mobster and soon-to-be governor, Lib Tyrant. While Train has to do it per orders from his superior, Sven wants to earn the money from Tyrant's bounty. During a party to celebrate Tyrant's assess to governor, Sven's right eye sees that Tyrant will be killed in five minutes and tries to avoid it. However, Train easily kills Lib and Sven pursues him to ask him why he did it. Before he can, one of Tyrant's bodyguards tries to kill Train, but fails. Train spares the bodyguard, who is then killed by Train's partner. Sven discovers later on that Train is the feared Kuro Neko (Black Cat), a Chronos Number (assassin) from the organization Chronos. While remembering his parents' deaths, Train meets a girl named Saya Minatsuki on the rooftop while she is singing a song.