The novel's main characters, sisters Nanna and Fride, have lived in a hidden bunker with their father for many years following a great catastrophe. Everyone is dead and nature has withered away.
When the girls one day dare to go our into the world without their father knowing, he catches the same mysterious illness that caused the catastrophe to begin with. With haste the girls have to leave to find medicine if their father is to have any hope of survival. They must travel to the city they lived in prior to the catastrophe - the very same city that their mother chose to stay in to work as a doctor in one last attempt to help the sick, desperate and dying people.
In spite of the gloomy scenario, The Fall is first and foremost a tale of life and love.