The Sevillano's guest is a story full of intrigues. The title alludes to the fact that a character who appears, the guest of the El Sevillano inn in Toledo, is the writer Miguel de Cervantes.

Susana is an unappreciated, naive and somewhat clumsy orphan who has lived since she was a child at doña Engracia's house, because her mother died a few days after she was born. In this house, which also houses three nephews of doña Engracia without a penny to one's name, Susana is the maid of all. Economic necessities lead Engracia to rent a room. Felipe, a handsome man with a bad reputation, will reply to the ad.

The frog test confirms Julita is pregnant. This is usually a great news. In this case, no. She is a victim of premarital sex, and he, Paco, a mechanic who, according to some theories of French biologist, explained by a podiatrist friend, will not be liable. Don Ramiro, the father of Julia, is a liberal-minded man, but when his daughter tells him that she will have a son who will not parent, seeking the solution of fatherhood in his gun regulation.

Paris 1900. Sharing a house in the Bohemian District are Roberto, a fledgling Musician, who is composing an Opera with his friend the poet Victor Duval; and the beautiful Cossette, daughter of a retired tenor, who goes up and down the stairs, taking advantage of Roberto's music to train her voice. The young bohemian musician does not know Cosette, but hears her sing daily. Instead, she's in love with Roberto and follows his steps as a composer.