Normal life if for the mundane. You don't learn this, until you lose it. Darkeness can descend quickly in a storybook world, and even quicker in the real one.
Darkeness comes on in the time of disease. As the flu sweeps nations, changes begin in the population. People change and life changes. Everything that people consider given, written in stone, is thrown upon its end.
And the fight for survival begins...
Zombies walk the earth, only they have no need to infect you, only to eat you.
They are the top of the food chain. And in order to survive, you have to outhink the undead and create another breed of humanity, a millenia in the making.
Or they will find you.