For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Don Andrea is unjustly murdered by Prince Balthazar, after which Balthazar finds an ally in Lorenzo as he romantically pursues Andrea's former lover, Bel-Imperia. Horatio becomes Bel-Imperia's lover and protector, but he is brutally murdered by Lorenzo's henchman so that Balthazar can pursue marriage with Bel-Imperia. Hieronimo discovers his son's dead body and vows to avenge his death.
Act II
Hieronimo plays a detective type while also dropping deep philosophical knowledge on revenge and justice. His efforts are constantly thwarted because of his relatively low social rank compared to the important snobs he must bring to justice. In the process he either fakes or is actually beset with mental illness.
Act III
After finally confirming who murdered his son, Hieronimo comes up with a plan to avenge the bad guys. He carries out this plan by producing a staged drama in which he and Bel-Imperia publicly kill all of the conspirators in Horatio's murder.