In the strange world that is entertainment, it’s not unusual for successful properties to be given unnecessary sequels or spin-offs of possibly dubious merit. Sometimes the original doesn’t even need to be any good for this to happen, it only need be bankable. This in itself could spawn quite the rant, but we'll save that for another day.
50 and G-Unit are putting on a sold-out performance somewhere in a fictional Middle Eastern setting. This is where the 'blood on the sand' comes in. They put on the performance; the people are pleased, but the concert promoter stiffs them and doesn't give 50 and G-Unit their payment… So, of course, 50 isn't going to leave until he gets paid, so he hassles the concert promoter, [saying] if he doesn't come up with the money now, there will be consequences. And instead, the promoter offers him a very valuable gift – something that's valuable to this particular country – a diamond encrusted skull...
So 50 gets the skull, and as he's about to leave this war-torn country, when they're ambushed and the skull is taken. They escape the ambush, but they're without the skull. So 50's motivated to get what belongs to him. So basically, throughout the game, he's trying to track these people down and find out who they are and why he was ambushed.
Of course he is. Now, I could proceed to describe how this particular entrant into cultural history is not going to do anyone any good, let alone the people who actually bother to play the game itself, but that much seems to be evident without needing anyone to point it out. But before anyone out there decides to jump to any conclusions accusing this potentially fine product of capitalising on sensitive political themes, rest assured, as the writer of the game “from