Train Heartnet, also known as "Black Cat," was an infamous assassin for a secret organization called Chronos...until he abandoned that cold-blooded existence to live on his own terms as an easygoing bounty hunter. But is Train's past as far behind him as he thinks? Train and River put aside their differences as they face off with Shiki, one of the most powerful members of the Apostles of the Stars. Shiki is determined to show that the Tao is the ultimate form of power, and he's going to take down Train, his friends and all of Chronos to prove it!