The play concerns Jaffeir, a noble Venetian who has secretly married Belvidera, the daughter of a proud senator named Priuli, who has cut off her inheritance. Jaffeir is impoverished and is constantly rebuffed by Priuli. Jaffeir's friend Pierre, a foreign soldier, stokes Jaffeir's resentment and entices him into a plot against the Senate of Venice. Pierre's own reasons for plotting against the Senate revolve around a senator (a corrupt and foolish Antonio) paying for relations with Pierre's mistress, Aquilina. Despite Pierre's complaints, the Senate does nothing about it, explaining that Antonio has senatorial privilege. Pierre introduces Jaffeir to the conspirators, led by bloodthirsty Renault. To get their trust, he must put Belvidera in Renault's care as a hostage. In the night, Renault attempts to rape her, but she escapes to Jaffeir. Jaffeir then tells Belvidera about the plot against the Senate, and against her father. She devises a plan of her own. Jaffeir will reveal the conspiracy to the Senate and claim the lives of the conspirators as his reward. It is only after Belvidera informs him of the attempted rape that Jaffeir agrees to do this, but the Senate breaks its word and condemns all the conspirators to death. In remorse for betraying his friend and losing his honour (by betraying his oath to the conspirators), Jaffeir threatens to kill Belvidera, unless she can get a pardon for the conspirators. She does so, but the pardon arrives too late. Jaffeir visits Pierre at his execution. Pierre is crestfallen because he is sentenced to die a dishonourable death and not the death of a soldier. He forgives Jaffeir and whispers to him (unheard by the audience) to kill him honourably before he is executed. Jaffeir stabs his friend, Pierre, on the gallows, and as a form of atonement commits suicide. Belvidera then goes insane and dies.
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