Many years ago, the last remnants of humanity were forced to retreat behind the towering walls of a fortified city to escape the massive, man-eating Titans that roamed the land outside their fortress. Only the heroic members of the Scouting Legion dared to stray beyond the safety of the walls – but even those brave warriors seldom returned alive. Those within the city clung to the illusion of a peaceful existence until the day that dream was shattered, and their slim chance at survival was reduced to one horrifying choice: kill – or be devoured!
The “Seven Deadly Sins”—a group of evil knights who conspired to overthrow the kingdom of Britannia—were said to have been eradicated by the Holy Knights, although some claim that they still live. Ten years later, the Holy Knights have staged a Coup d'état and assassinated the king, becoming the new, tyrannical rulers of the kingdom. Elizabeth, the king's only daughter, sets out on a journey to find the “Seven Deadly Sins,” and to enlist their help in taking back the kingdom.
In 2071, roughly fifty years after an accident with a hyperspace gateway made the Earth almost uninhabitable, humanity has colonized most of the rocky planets and moons of the Solar System. Amid a rising crime rate, the Inter Solar System Police (ISSP) set up a legalized contract system, in which registered bounty hunters, also referred to as "Cowboys", chase criminals and bring them in alive in return for a reward.
