The story of the opera is laid in Portugal, time, 1777.  The opening scene discloses the ruins of a castle in the mountains, near the monastery of St. Huberto, where Don Henrique, nephew of the Count de Campo Mayor, Minister of Police at Coimbra, overtaken by a storm, seeks shelter.  At the time of his misfortune he is on his way to take part in the approaching coronation, and also to sign a marriage contract with his cousin Diana, daughter of the Minister of Police.  He solaces himself with a song ("Roll on, Roll on"), during which he hears the blows of hammers in a distant cavern, and on looking round discovers Rebolledo, the chief of the coiners, and two of his comrades, with his trunk in their possession, the contents of which they proceed to examine.  Don Henrique conceals himself while Rebolledo is singing a rollicking muleteer’s song ("O’er Mountain steep, through Valley roaming").  At its conclusion Rebolledo, about to summon the other coiners to their secret work, discovers Don Henrique, and thinking him a spy rushes upon him.  He is saved by the sudden entrance of Catarina, the leader of the gang, who tells the story of her life in a concerted number that reminds one very strikingly of the bandit song in “Fra Diavolo.”  After examining Don Henrique, and, to his surprise, showing an intimate acquaintance with his projects, she returns him his property, and allows him to depart on condition that he shall not speak of what he has seen for a year.  He consents; and then follows another of the concerted numbers in which this opera abounds, and in which occurs a charming rondo ("The Young Pedrillo"), accompanied by a weird, clanging chorus.  Before he can effect his departure the gang find that they are surrounded by troops led by Don Sebastian, a friend of Don Henrique.  The coiners, in company with the latter, however, make their escape in the disguise of monks on their way to the neighboring monastery, singing a lugubrious chorus ("Unto the Hermit of the Chapel"), while Catarina and Rebolledo elude the soldiers by taking a subterranean passage, carrying with them a casket containing some mysterious jewels.

The second act opens in the Chateau de Coimbra, and discovers the Count, Don Henrique, Don Sebastian, and Diana.  The first scene reveals to us that Don Henrique is in love with the mysterious Catarina, and that Diana is in love with Don Sebastian.  In a sportive mood Diana requests Don Henrique to sing with her, and chooses a nocturne called “The Brigand,” which closes in gay bolero time ("In the Deep Ravine of the Forest").  As they are singing it, Don Sebastian announces that a carriage has been overturned and its occupants desire shelter.  As the duet proceeds, Catarina and Rebolledo enter, and a very flurried quintet ("Oh, Surprise unexpected!”) occurs, leading up to an ensemble full of humor, with a repetition of the brigand song, this time by Catarina and Diana, and closing with a bravura aria sung by Catarina ("Love! at once I break thy Fetters").