Amid the political turmoil of the Glorious Revolution where conspiracy and intrigue are commonplace, fencing master Don Jaime Astarloa tries to live as he always has.
A concierge, at one point, mentions to Don Jaime that the navy has rebelled in Cadiz, which actually occurred when Admiral Juan Bautista Topete mutinied.
Some discussions in the book run contrary to historical fact, such as Carreño's guess that Baldomero Espartero would become regent.
Luis de Ayala and Minister Marfori are said to have had intimate relations with the Queen, which is wholly possible due to her alleged nymphomania.
A minister, later revealed to be Joaquin Vallespin Andreu, uncle of Luis de Ayala, meets with an apparently wealthy blackmailer.
Shortly, money and an envelope full of "names and addresses" changes hands, and the scene ends with a reference to the historical time frame, 1866 during the reign of Queen Isabel.
The subsequent discussion reveals that Luis de Ayala has apparently resolved to abstain from politics despite invitations to resume his post.
Later, Luis mentions a Holy Grail, which turns out to be the "Treatise on the Art of Fencing," that Don Jaime is working on.
The depth of Don Jaime's passion for fencing is revealed by a description of the lengths to which he has gone in search of an "unstoppable thrust" that is impossible to parry, which he is not sure even exists.
He repeatedly praises the pupils in front of their parents, often making gross exaggerations about their talent in order to retain his clients.
Finally, Carreño shares none of Don Jaime's honor, flaunting wild political theories as fact in order to gain attention.
When faced with the claim that fencing masters will one day cease to exist, he laments that with them will die "all that is noble and honorable about [battle]."
He is fascinated with her, paying attention to certain characteristics that he finds odd, such as short fingernails and a small scar near her mouth.
She asks him to teach her a secret "two hundred Escudo" thrust, and he declines with finality, becoming angry when she offers additional money.
As the clock strikes three, Don Jaime begins to doubt the possibility of an unstoppable thrust, hearkening back to the words of his old master.
Don Lucas and Cárceles, monarchist and republican respectively, argue heatedly while Carreño and Romero step in occasionally.
Cárceles blames Queen Isabella and her continual vacillation between liberal and conservative positions for the country's troubles, and warns the others that opposition to her rule is beginning to cross party lines.
He lets the conversation continue until he feels that he is no longer thinking clearly, at which point he ends the talk and escorts Adela home.
One morning, Luis de Ayala uncharacteristically refuses to fence Don Jaime, citing an unsteady hand.
At the crime scene, he noticed with dismay the cause of death: a foil wound in the throat, characteristic of the secret thrust that he had taught Adela.
He goes home and begins reading the letters, finding nothing but lists of names and a strange reference to silver mines.
Unable to deduce a motive for killing de Ayala, Don Jaime decides to obtain the help of someone well versed in Spanish politics.
He forces entry into Cárceles' home, only to find his friend strapped into his bed, tortured out of his mind with a mass of razor cuts.
Finally, Don Jaime employs a redoublement, cutting over Adela's arm for a lethal thrust through her eye into her brain.