Somewhere in the barren desert hellscape of post nuclear war Australia, in a fortified compound, someone has asked Santa Claus for a wrist rocket slingshot, a pellet gun, and an archery set for Christmas. And so Santa Claus comes on Christmas to deliver what he thinks are ostensibly toys to this good pair of children, little knowing they might be their, and his, only means of survival in the events soon to take place (!).
When Santa Claus travels to deliver the weaponized toys to the children, the vicious traveling nomads notice him, and seeing he does not require scarce gasoline to run his vehicle, they all want to take possession of his sleigh. They also want to eat Santa's reindeer. And so Mad Max must help Santa Claus fight these villainous mercenary nomads to save himself and Christmas. (And the weapons/toys he's delivering play a crucial role in saving the day! Brought to you by weaponized toy manufacturers.)