It is 1605. Miguel de Cervantes, flush with the success of his book, Don Quixote, is now in Valladolid with the Royal Court, following them to write the chronicle of the signing of peace between Spain and England. Lope de Vega comes and, after exchanging some barbs with the writer, shares some interesting news with him: the great William Shakespeare is coming with the English representatives, and Lope has been tasked with preparing a play for their entertainment. Cervantes gets quite angry at his rival gaining one over him.
In 1882, Amelia finds her mother reading one of the books she read to her when she was a little girl, and her mother says she plans to give them to a friend of hers that is about to become a grandmother, seeing that Amelia is starting to become an Old Maid.
In the present, Alonso realizes things with Elena are getting quite repetitive, knowing what she will say - only for her to ask him whether they should take a break. The two argue because Alonso would like to see her pregnant while Elena mentions she does not want to bring children to a cruel world.
In the Ministry, Lola complains to Ernesto because she has yet to be assigned a mission, with Ernesto counseling her to be patient. Irene and him have to go to 1982, and Ernesto mentions he is worried not just about Lola, but about Pacino - who is still trying to apologize for the mess he caused by letting his former lover Marta escape, which led to the new mess in 1808. But, while Ernesto and Irene are going to 1982 to find clues about Marta, Salvador receives a call from 1605: someone has tried to poison the English diplomat in charge of negotiations. He sends Amelia, Alonso and Pacino to 1605, to ensure no one can mess with the treaty signing.
In 1605, Cervantes meets with the Duke of Lerma, the king's favorite and pretty much the most powerful man in Spain, and requests that he be the one to represent a play for the English while Lope takes care of the chronicle, but Lerma is unwilling to change that, so Cervantes requests something different: to be allowed to meet with Shakespeare. Lerma accepts.
The trio is now in 1605, and they are assigned different roles: Amelia will become the Queen's handmaiden, while Alonso and Pacino will have to act as escorts/bodyguards to the English diplomat, Admiral Charles Howard
. Amelia soon gets along with the Queen, who tells her she feels lonely in a court dominated by Lerma. While Alonso (with much reluctance) and Pacino take the English to a tavern, Amelia manages to get the Royal Cook to tell her about the waiter that took the poisoned food.
Ernesto and Irene's detour to 1982 yields quite a lot of information - and yet another conquest for Irene - but soon they hit a snag: all the documentation the 1982 Ministry has on Marta is false, as are most of her personal photographs.
In 1605, the Queen decides to talk with Lope de Vega and Amelia unsuccessfully tries to avoid the encounter, but fortunately Lope does not blow her cover, and the Queen reveals her intention: she wants Lope's play to be about Lerma's corruption.
In the present, Ernesto and Irene's investigation remains fruitless, until Irene has an "Eureka!" Moment: one of the notes in Marta's agenda points to a gate and a year, which could be where she is hiding.
In 1605, the King has invited the English to a hunt. Howard considers the Spanish version of a hunt (shooting birds) boring, so he makes a bet with Alonso: whoever shoots down more birds wins. Alonso accepts.
Meanwhile, Velázquez has finished the waiter's portrait: it's the same man that killed the Russian spy that had tried to kidnap Hitchcock, and he is among the servants helping load the guns for the hunt. Amelia rushes to warn her partners, as the killer prepares to shoot Howard with a sniper rifle. Pacino, however, manages to find him and shoots before he can kill Howard. While Howard wins the bet and takes Alonso's sword, Pacino finds the would-be killer carries an Ángel Exterminador ring. In spite of catching the would-be killer, Salvador keeps the team in 1605, just in case. Lola also looks like she is interested in several lost paintings.
Lerma meets with Lope: he has learned about Lope's play, and he is not happy. Lope tries to convince him to allow the representation to take place, but Lerma threatens him with the loss of his license to produce theater. When Amelia realizes Lope has acquiesced with Lerma's demands, he tells Lope her regard for him has vanished, although she does recover her good mood when she meets William Shakespeare later.
That night, the King invites Alonso, Pacino, Cervantes (who seems to recognize the former two), Lerma, Howard and his aide to a card game. The English win, but Alonso realizes Howard's aide is cheating, and the two English retire, embarrassed, and Lerma convinces the King to cancel the treaty.
Amelia speaks with the Queen, who feels down after learning of Lope's betrayal of her plans, but Amelia cheers her up, telling her she has told Shakespeare of the Queen's troubles - which he intends to write as a tragedy called Macbeth - and the Queen has the idea to have Shakespeare meet Cervantes behind Lope de Vega's back as revenge, which is when Amelia learns about the King's decision. Their copy of the chronicle begins to change, showing that war will fire up again with the change of history, and Alonso, Amelia and Pacino begin to bring up the times each of them has screwed up, before they realize they have to act fast. Amelia sees the Queen and sends Pacino to find the English and make sure they do not learn of the King's decision, while she goes to speak with the Queen. The Queen manages to convince the King to change his mind, which angers Lerma, but he can do nothing.
The treaty is signed, and history is restored, but a last problem surges once more when Lope de Vega sees Cervantes gift Shakespeare a copy of Don Quixote, sparking his jealousy. Lope goes furious to Cervantes' office in the Royal Palace, and the two men begin to fight, but Amelia arrives and calls them out for their immaturity.
Mission accomplished, and the team returns to the present. During the debriefing, Angustias comes in and warns Salvador that Lola has gone missing, taking some of Velázquez's paintings with her. Ernesto feels crushed for the betrayal, as well as Salvador.
Alonso listens to a message Elena has left on his phone, as she takes everything she still has in the flat he shares with Pacino. And Amelia finds the photograph where she appeared with Julián and their daughter - only that now she is the only one in there.
