Sambou and Aritz travel through the world's end in search of something they lost.

In the borderless Europe of the 21st century, one border still separates Spain from France, marked by the Bidasoa River. On this river lies Pheasant Island, a tiny piece of land that alternates between Spain and France every six months. When the body of an illegal immigrant is discovered on the day of the border shift, Nassim, one of the survivors, becomes the target of a violent manhunt by French authorities as he tries to cross the border. This chilling event will change the lives of Laida and Sambou, an interracial couple.

Joxean is not aware of the border in her country. He moves every week to sell pigs. For Kamaru, the border means every obstacle and danger. They both have to fight the same enemy.