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 receives a desperate plea for help from Karl, the mayor of Rubeck City and one of Chronos's top brass, because a serial murderer with mysterious powers is terrorizing Karl's town. Eve offers herself as bait to lure the killer out, but will she be caught in a deadly trap?