After the death of their son in a car accident, Ana and Pablo decide to move to the mountains to open a country house. Their best friends, Guille and Bea, have come from the city for the opening dinner, but something goes wrong. A strange aurora borealis leaves them isolated, while Guille suffers a sort of attack, severely injures another, and tells an alternate version of their lives: he knows only Ana, his partner according to him, who died in the accident, but not their son, who is still alive. At first, they will think Guille is crazy, but gradually they will begin to wonder if what he says might be real.