It's the zombie apocalypse! Only, the zombies are already gone. I seem to remember them leaving for somewhere, but they will never return and no longer pose a threat.

Still, my family, which survived the event with me, seems determined that the only way to safety is a trip to some distant place.
So, off we travel, looting and having fun along the way in the empty cities we pass. We eventually steal a train and ride it towards our destination.

There was more detail, but it has faded in my mind to the point where I can't accurately describe it.