Doctor Guillermo García, a communist sympathiser, remains living in Madrid after the takeover of the country by the Francoists.

To save his life, he is forced to hide and adopt the false identity of Rafael Cuesta Sánchez, facilitated by his friend Manuel Arroyo, a spy for the Republican side.

Years later, in 1946, García meets Arroyo again as the latter returns from exile to carry out a secret mission in the city under the assumed identity of Adrián Gallardo, a former member of the Blue Division, who is considered a war criminal for collaborating with the Nazis.

[1][2] Arroyo, in the guise of a Blue Division veteran, emigrates to Argentina and infiltrates the ratlines between Juan Domingo Perón and Franco in favor of the Nazis who feel safe in South America, with the promise that the United States, through the CIA, will intervene at some point against both dictators.

[3] An adaptation of the novel of the same name by Almudena Grandes, the series was written by José Luis Martín and directed by Joan Noguera [es].