Nico is a computer programmer from Coruña in Galicia. On a business trip to the city of Bergen in Norway, he visits the quays of Bryggen, a place he has been to before. He buys a couple of postcards from a shop there and, much to his surprise, discovers that one of them has captured the moment when he and his friends visited Bergen on an Interrail trip after leaving school ten years earlier. There they all are: Óscar in his Deportivo football shirt with Bea; Nico with the slightly pretentious Mía, poring over a map; the Italian exchange student, Piero, a few feet behind them. But where is Nico's girlfriend, Aroa, and his best friend from school, Xacobe, the other two members of the group? Nico is shocked to find that they are in a corner of the postcard away from the others and are kissing. He resolves to unearth all the mystery surrounding that trip and the bitter month of September that immediately followed, when a tragedy occurred, a tragedy that split the group apart and from which no one has recovered. He will invite all his friends to a school reunion and, by gauging their reactions to the postcard, finally learn the truth of what happened.