I.ii Balthazar has been captured in battle by the victorious Spanish army during their war with Portugal. Both Horatio (Hieronimo's son) and Lorenzo (the duke of Castile's son) claim Balthazar as his own captive. The King awards Balthazar's ransom to Horatio while Lorenzo is offered the glory and right to keep Balthazar as a guest.

I.iii In the Portuguese subplot, Villuppo claims Balthazar is slain. He slanders Alexandro, claiming that he actually shot Balthazar in the back during the battle.

I.iv Bel-imperia takes up with Horatio, who was Don Andrea's best friend, and makes love to him with the hope of turning him to her purpose of revenging the death of Don Andrea. Horatio tells her how Don Andrea was killed. Balthazar killed him after the halberdiers had knocked him to the ground.

Lorenzo, a Machiavel, befriends Balthazar, who is in love with Bel-imperia (Lorenzo's sister). While Bel-imperia and Horatio are courting in Hieronimo's arbor, Lorenzo and Balthazar surprise them. Bel-imperia rejects Balthazar's love. As she leaves, she drops her glove for Horatio thus demonstrating her favor. Balthazar is enraged.

A banquet is brought in to honor the princely prisoner Balthazar. Hieronimo presents a masque for the King and his guests.

I.v Don Andrea objects to having been brought from Hades to see his murderer fêted. Revenge entreats his patience.

II.i Pedringano, Bel-imperia's servant, tells Balthazar and Lorenzo that his mistress is in love with Horatio. The conspirators and their servants, Pedringano and Serberine, plan to kill Horatio.

II.ii Pedringano secretly admits the conspirators to the arbor (above?), where they watch Horatio and Bel-imperia courting. Balthazar is further enraged, believing Horatio an "ambitious villain."

II.iii The King of Spain and his brother Cyprian, Duke of Castile, plan to marry Bel-imperia to Balthazar in order to bring peace to Spain and Portugal.

II.iv Horatio and Bel-imperia are courting in the garden. Lorenzo, Balthazar, Pedringano, and Serberine, in disguise, surprise the lovers. They kill Horatio and hang him on a tree in the arbor. They then kidnap Bel-imperia and lock her in an upper room of their house.

II.v Hieronimo, hearing the commotion in his arbor, rushes down and finds his son's body hanging on the tree. Isabella, Hieronimo's wife, joins her husband in the arbor and they both lament.

II.vi Don Andrea again objects. Seeing the murder of his friend Horatio has only increased his pain. He begs for a conclusion. Revenge scolds him, "Thou talk'st of harvest when the corn is green." He tells Andrea to watch and wait.

III.i Meanwhile, back in Portugal, Villuppo, a Portuguese courtier and Machiavel, has succeeded in convincing the Viceroy of Portugal that Alexandro (a Cassio-type Portuguese nobleman) killed Balthazar (the Viceroy's son) during the battle. Having not learned of Balthazar's capture by the Spaniards, The Viceroy sentences Alexandro to death. An emissary from Spain relates having seen Balthazar alive and well as a captive of Spain. His news comes just in time to save Alexandro. The Viceroy sentences Villuppo to death for having conspired against the life of Alexandro. A pact is agreed upon between Spain and Portugal, and the Viceroy sets out for Spain to conclude the peace.

III.i Hieronimo delivers his "O eyes, no eyes" speech in soliloquy revealing his loss of faith in Justice.

Bel-imperia drops a letter from her chamber to Hieronimo, who is below. The letter, written in her own blood, tells of what happened in the arbor, of Lorenzo and Balthazar's guilt. Hieronimo mistrusts the letter, fearing it is a trap to catch him conspiring against the life of Balthazar, the heir apparent of Spain, and against Lorenzo, the King's nephew. He awaits confirmation.

Hieronimo asks Pedringano of Bel-imperia's whereabouts, which raises suspicion in Lorenzo's mind that Balthazar's servant, Serberine, has betrayed them.

III.iii Lorenzo has Pedringano lie in wait for Serberine that night. In order to close Pedringano's mouth as well, Lorenzo alerts the constabulary of Pedringano's actions. When Pedringano shoots Serberine, the watch capture Pedringano.

III.iv Lorenzo assures Pedringano that he has used his influence to secure Pedringano's pardon. He sends a Page to the execution with a box, which supposedly holds the pardon.

III.v In a short sequence, the Page enters alone and discovers that the box is in fact empty.

III.vi Pedringano, believing he will be pardoned, goes to his execution flouting the authority of the executioner and Judge (the judge is Hieronimo). He remains impudent to the last moment when the box is opened to reveal nothing, and Pedringano is "turned off" (hanged) as he screams in rage and betrayal.

III.vii Hieronimo feels lost and confused, unable to avenge Horatio, he has done nothing but "surcharged the air / With ceaseless plaints for my deceased son". Hieronimo is shown a letter that the executioner found in Pedringano's pocket. It relates all of the details of Horatio's murder. Hieronimo's suspicions are confirmed.

III.viii Hieronimo's wife, Isabella, speaks with her maid. She, too, is on the verge of insanity, frustrated by her inability to "find them out that murdered my son".

III.ix Bel-imperia appears at her window. She, too, wonders what has happened to Justice.

III.x Lorenzo and Balthazar free Bel-imperia and attempt to justify themselves to her. They explain that what they did was done to preserve her honor and reputation. They again attempt to make Bel-imperia love Balthazar. She again rejects him and leaves. Lorenzo and Balthazar believe their explanation was convincing, however, and decide to go give it before the King to excuse their actions.

III.xi Two Portingales meet Hieronimo in the street and ask directions to Lorenzo. Hieronimo answers with an elaborate metaphor that they should follow Guilty Conscience to find him "in a brazen caldron, fixed by Jove / In his fell wrath upon a sulphur flame" where Lorenzo may be seen "bathing him / In boiling lead and blood of innocents." The Portuguese men laugh at the jest and believe the old Hieronimo is either insane or senile.

III.xii Hieronimo enters with a poniard in one had and a rope in the other and delivers his "This way or that way" speech, contemplating suicide. He flings the instruments of destruction away as the King enters.

Hieronimo tries to reach the King to beg for justice, but is prevented by Lorenzo, who convinces the court that old Hieronimo is mad.

III.xiii At the play's turning point, Hieronimo enters with a book in his hand. He resolves to resort to private vengeance now that public justice has failed.

Three citizens and an old man come to him and ask him to adjudge their case. The old man's son has been murdered, and he seeks justice. Hieronimo, reminded of his own plight, is pushed further towards distraction. In his frenzy, Hieronimo tears up the petitioners' bonds and declarations before running from the stage. He reappears a moment later. He claims he has done their papers no harm because they do not bleed, and then exits again only to reenter yet again. He commiserates with the old man and both go off together.

III.xiv The King of Spain and Viceroy of Portugal make peace.

Castile admonishes his son, Lorenzo, that he has heard rumors that he has wronged Hieronimo. If the rumors are true, Castile says that he will be ashamed to answer for Lorenzo.

Balthazar enters with Bel-imperia, whom he calls his love. Castile tells her to be cheerful, that life must go on even though Don Andrea is dead.

Hieronimo enters. Castile asks whether it is true that Lorenzo has blocked Hieronimo's suits to the King. Hieronimo violently denies it and offers to fight anyone who would slander Lorenzo "that loved my son so well". The scene ends with Hieronimo suspecting that Castile is part of the conspiracy with Lorenzo. He says, "Ci mi fa più carezze che non suole, / Tradito mi ha, o tradir vuole." (He who gives me more caresses than is usual seeks to betray me or has betrayed me already).

III.xv Don Andrea calls on Revenge to awake. He believes that Hieronimo has joined with Lorenzo. Revenge assures him that Hieronimo cannot forget his son Horatio and will wreak his vengeance in the fullness of time. He shows Don Andrea a dumb show in which Hymen, all in black, quenches two nuptial torches in blood. Andrea understands and is content to watch.

IV.i Bel-imperia and Hieronimo conspire to be avenged upon the murderers of Don Andrea and Horatio.

Balthazar and Lorenzo enter from the King. The King has asked Hieronimo to devise an entertainment to fête the Viceroy. Hieronimo agrees. He immediately casts Balthazar, Lorenzo, Bel-imperia, and himself in the masque he will present. He will draw upon a tale "of a Knight of Rhodes" told in the "chronicles of Spain". It will be the masque of Solimon and Perseda in which Solimon kills Perseda's husband in order to have her. She will kill Solimon and then herself. They all agree to participate.

IV.ii Isabella, Hieronimo's wife, commits suicide (after first "running lunatic" and tearing down the arbor where Horatio died).

IV.iii The court believes that Hieronimo, who has behaved most strangely because of his great grief, is also mad.

IV.iii Hieronimo prepares the stage by "knocking up" a curtain. Hieronimo asks Castile "That, when the train are passed into the gallery, / You would vouchsafe to throw me down the key." Castile agrees. Secretly, Hieronimo has added Isabella's death to his list to be avenged.

IV.iv The royal party enters, and the play begins. The tragedy calls for the characters to each speak a different language. At the moments indicated for the characters played by Lorenzo and Balthazar to be stabbed, real knives are substituted for stage props, and Hieronimo and Bel-imperia kill them unbeknownst to the stage audience. Bel-imperia, possibly for grief over her lost love Don Andrea and her responsibility for the deaths of Horatio and her evil brother, stabs herself with a real knife at the point her character is to commit suicide.

Hieronimo reveals that all are truly dead and shows the body of his slain son Horatio. He is caught and asked why he has done this, but he bites out his tongue to keep from being made to talk. He is forced to write down his confession. He calls for a knife with which to mend the nib of this pen and stabs the Duke of Castile and himself with it instead.

All die.

IV.v Don Andrea glories in the act. He and Revenge return to the underworld to greet the righteous and punish the wrong.