A family unravels during a bloody, berserk summer, when a horrifying plague transforms a small town into the flesh-eating walking dead.
A family of four - Dino, his wife Pernille and their children, the young Maj and teenager Gustav - are living in idyllic Sorgenfri, Denmark.
An elderly neighbour, Elna, comes running to the party and says her husband has died, but upon investigation his body has gone missing.
Over the course of several days, a deadly virus that reanimates its hosts into hostile killing machines sweeps the neighbourhood, but Dino lies to the children that everything is alright.
The military keeps the families supplied, but each house is kept strictly incommunicado and wrapped with plastic sheets, and the power frequently fails.
During the night, some of the neighbours are dragged from their homes, placed in the back of trucks and transported to a "safe space", as the military tells them.
He decides to open the back of the trucks to free the patients, and is discovered and flees, not knowing that he has unwittingly freed the infected.
Abandoned, Casper joins Dino and prepares for a siege while Maria grows progressively sicker, and Ninus has gone missing.
Going scouting, Dino and Casper find the area closed off by a wall erected by the military and are forced back under gunfire.
At the height of the whistling's crescendo, a deep boom resounds; the screen cuts to black and briefly flashes the words "WHAT WE BECOME", then the end credits begin to roll.