Marcelino Sanz de Sautuola y de la Pedrueca, in 1868, accidentally discovered Patheolitic paintings with the help of a hunter named Modesto Cubillas inside Altamira's caves, located in Cantabria, north to Spain. Trying to expose their discovery to the academic world for that they study the paintings, Sautuola crashed against the skepticism and discredit of all experts, who claimed that the caves were false and the paintings made for the own Sautuola, in a effort to get rich. Looking for the truth, Sautuola was the rest of his life fighting to prove that those paintings were real, trying to restore his innocence from the accusations of falsehood launched against him.

The fates of Henry - a cynical American correspondent who has lost his soul - and Teresa, one of the Republic's censors and in charge of overseeing the news that journalists can send abroad, cross in Gernika.