The story is relatively simple and direct, not crowded with comic subplots, as many a Renaissance drama is. That is not to say it is without humor. There's some very funny stuff. It just is more integrated into the work as a whole. Peribanez and Casilda are a newly married couple, so in love with each other it's kinda gross. On their wedding day a bull goes mad, gores a horse and then injures the feudal lord, the Commander. He is brought to Peribanez's house unconscious, possibly dead. Peribanez (also called Pedro) rushes out to get a doctor. In his absence, the Commander awakes to the entreaties of Casilda. He falls into an all consuming love/lust for her.
The Commander then plots some ways to woo Casilda: he give her husband mules and her jewelry; he secretly has her portrait painted; he sends has lackey to woo her cousin. Meanwhile, Pedro is sent to Toledo to get a statue refurbished and sees the portrait. He gets jealous. While Pedro's away, the Commander takes the opportunity to seduce Casilda, only to discover that she is fanatically in love with Peribanez and will not be moved.
Pedro returns, wracked by jealousy and guilt, and discovers his wife to be faithful. He rewards his wife with renewed vows of love. The Commander, now enraged and more than determined to have his way with Casilda, plots to send Perdo off to war as captain of a contingent of peasants. With the husband out of the town he returns to Casilda. Pedro however has suspected this. Armed with a sword and a newly gifted knighthood, he returns from the war in secret and hides himself in Casilda's chambers.
The Commander comes in and proceeds to rape Casilda. Pedro reveals himself after an unaccountable hesitation and kills the Commander, his servant, and Casilda's cousin who abetted the invasion. Peribanez and Casilda flee. The Commander, soon to die, condemns himself and exonerates Pedro, before dying in the arms of his lieutenant.
The lieutenant goes to the King who is looking over his assembled army (needed to drive the Arabs and Moors from Spain), of which Pedro and the Commander were to be part. He explains the Commander's absence due to death for which Pedro must be executed. A search is made for him. Pedro turns himself in and explains why he did what he did. The King, and Queen, are sympathetic, forgive Pedro, and give him command of the entire regiment. Casilda, who has been silent since her near rape is taken under the Queen's protection.
There is a final scene in which Casilda disrobes for Pedro, but only to put her newfound finery. There is a deep and palpable sense that the love they once shared, that was so intense it was nearly comical, has been compromised and lost. End of play.
I liked this play. I would very much like to read another adaptation. This one seemed a trifle modern textually modern. There are nods and hints at what must have been a very heightened speech in the spanish. I imagine this might be what reading Shakespeare in a modern adaptation into another language must be like,. Structurally it decidedly part of its time. The characters are all tropes from the Renaissance theatre, and the soliloquy is much in evidence.
I am curious if the last scene is in the original Lope de Vega. It definitely has a more modern feel to the end. Traditionally, with the marriage saved and wrongs righted the play's ending would be deemed happy. The tinge of loss that haunts that last scene is an excellent addition. As it it wordless I am pretty sure it is a modern touch but if not De Vega was well ahead of his time.