After an unfortunate horrible world war 3, All leaders of great nuclear armed country pressed button of nuclear detternence, the world gets into chaos and holds breath as all silos in the world is emptied into each other's capital.
Instantly millions of people die including the presidents of the country, however those who died quickly were at mercy because what was upcoming was far far more deadly, after the global blast the whole world gets shook to core and people who were unfortunate to survive gets the nuclear radiation along with decades worth of fertility diseases, people die from radiation after a month of two and the global population declines to only a few millions remaining of the small countries who were fortunate to survive.
But that was the worst mistake of them, "To survive" what did survival meant to them? Because after aftee a month a fate worse than death came.