A future where water is hard to find...
Rule #1: Don't look for it in the desert, LOL.
It would be a silly future if in fact ALL the water was gone, unless those nasty spacefolk from Battle: Los Angeles returned and poached it.
On another note, is that "Big Dog" in the movie poster?
"You will not be saved by the god Plutonium. In fact, YOU WILL NOT BE SAVED!"