It's the story of two sweepers - Train Heartnet, who was once the legendary assassin known as Chronos XIII or 'Black Cat', and Sven Vollfied, a former police officer. As sweepers, they capture criminals for money - kind of like bounty hunters. Soon their job starts becoming more dangerous, however, as Train's old 'friend' Creed appears with a gang of humans gifted with strange powers...

This book is printed "manga style", in the authentic Japanese left-to-right format.