From the back of the box:
The World of Bloodshadows is a setting for use with the MasterBook rules system.
From the back of the World of Bloodshadows boxset:
The World of Bloodshadows is a roleplaying game setting that comines pulp adventure with dark fantasy. Tough detectives in weathered trenchcoats wap biting comments with vampires in evening gowns. Humans walk down dark streets side by side with demonic breeds and long-dead ghouls. And death - or Undeath - waits around every corner.
Go outside the cities and discover the terrors of the Wilderness. Even the most powerful shapeshifter or sorcerer fears what waits in the ruins...
Your weapons in the world of Marl are magic and technology - but neither replaces a good head on your shoulders.
And you'll have to work to keep it there.
This box contains all you need to begin play: the Bloodshadows WorldBook, the MasterBook rulebook, two ten-sided dice, and the MasterDeck, a card deck for use with the MasterBook game system.