Lucía manages to enter as a secretary in the British Mining Company after very demanding tests. Miss Parker, the chief of staff, and Peter, the manager, are fascinated by his exceptional qualities. But Lucía, although happy, has lied both in the interview and her boyfriend, the Governor, Francisco Martín, whom she wants to marry. Intrigued by Peter, she soon suspects that things are happening in The Company that go beyond the administrative. For their part, the British are suffering from the shortage of diesel to transport the mineral from Riotinto. Edward, an undercover spy, wants Peter to return to MI6, but a trauma from the past prevents him from doing so. In addition, Peter has become addicted to opium painkillers. The relentless advance of the Nazis in Europe and Churchill's rise to power, prompt Peter to enter a dangerous mission, discovering that the Nazis are behind the lack of fuel. Lucia, who will be directly involved in the war between the two sides.

After the shooting in the port, Edward and Juan are injured and Juan asks his sister Lucia to look for Peter to give him some important information. For his part, Francisco, Civil Governor in Huelva, has serious problems after the incident and interrogates his fiancée Lucía about the involvement of the British. While the British believe that Edward is dead, Miss Parker pressures Peter to lead the team of spies and shows him the war room, the center of British espionage and London sends a new agent: Victor, Peter's best friend. But it brings back painful memories of a mission in Poland where he lost Sylvia, his fiancée.

An Italian spy arrives in Huelva who brings classified information that both sides want. The Nazis go ahead and hide it in the German Consulate. Peter manages to contact the Italian and offers him to leave the country, without being very clear about his loyalties. Lucía, after seeing the war room, discovers that there is a team of spies in La Compañía. The British are going to celebrate the King's feast day and Francis invites Lucia, who fears being fired when Peter discovers that she is the governor's girlfriend. This invitation brings to light old secrets that implicate Rocío, Francisco's mother, and Cinta, Lucía's mother: he must prevent Lucía from going to the party with her son. For his part, Schneider appears at the party with Hanna, his daughter, who notices the governor. The English will use the party to get the Italian out of the country and Lucia is unwittingly involved in the mission.

The British spy services in Huelva, with Peter at the head, are going to have to be more effective as there is not much time left. The Germans have arrived in Paris and the swastika is already flying on the Eiffel Tower. London sends modern microphones that will help the team listen to the conversations of the Nazis in the Club. This way they can get ahead of their steps. Especially now, that Italy has entered the war supporting Germany. Lucia accepts Francisco's marriage request, stirring up her mother's ghosts again, and Cinta, desperate, will go to a priest to seek peace and finally confess the secrets she is hiding.

The Nazis blew up the dock and only Lucia has seen the saboteur. But she is devastated by Agatha's death and angry at Peter for putting them in danger. The club's microphones reveal that the saboteur is going to Seville, so Peter asks Lucía to accompany him. They will pretend to be married and look for the guy, whom Lucía must recognize. Schneider extorts Amparo for bringing British spies into the German party and she will pay a heavy price for saving her life. Peter and Lucia will reveal themselves as the perfect "spy couple".

Peter, although in love with Lucia, does not trust her and will do anything to prove his loyalty. The Nazis' plan against the British ambassador, who is coming to visit Huelva and of which Lucía will be the translator, will bring everything to light.

Shocked by Juan's death, Lucía decides to stop her activities as a spy. Nazis and English pressure her. The arrival of refugees and the danger that Amparo runs because she is Jewish, will make her help the English as a tribute to Juan.

The crash of an English plane in Huelva will give the team information that will be the last mission before leaving Spain. Lucia, pressured by Schneider, will have to endanger everyone's lives.