"Ah, yes. You see, it all started in 1939. This guy called Hitler did a bunch of bad stuff and started a war. This war raged on for three years. Then one day, there was an alien invasion! Hitler, feeling guilty about all the terrible things that happened, he decided he was going to kill the aliens and then wipe everyone's memory. He had his sniper rifle pointed at the mothership, when suddenly a stranger from the future stopped him! The aliens then attacked everybody, ending civilization as we know it."