The Pirates of Penzance

Background
After the sensational success of H.M.S. Pinafore, many American performing companies presented unauthorized versions of that opera. Gilbert, Sullivan and Carte decided to prevent that from happening again by presenting official versions of their next opera, The Pirates of Penzance, or The Slave of Duty simultaneously in England and America. The opera premiered on December 31, 1879 at the Fifth Avenue Theater in New York with Sullivan conducting, but a single performance had been given on the previous day at the Royal Bijou Theatre, Paignton, England, to secure the British copyright. Finally, the opera opened on April 3, 1880, at the Opéra Comique in London, where it ran for 363 performances, having already been playing successfully for over three months in New York.
Plot
The curtain rises on a scene of revelry. Frederic has just completed his pirate apprenticeship and is being hailed as a fully-fledged member of the gang. That he had been indentured with them at all was a mistake. When he was a lad his nurse was told to take and apprentice him to a pilot, and when she discovered her stupid blunder she let him stay with the pirates, and remained with them herself as a maid-of-all-work rather than return to brave the parental fury. Frederic, at all times the slave of duty, has loyally served out his time, but now he announces that not only will he not continue at a trade he detests, but he is going to devote himself heart and soul to his old comrades' extermination. The declaration turns the camp from joy into mourning, but these very scrupulous pirates have to admit that a man must act as his conscience dictates, and they can only crave that the manner of their deaths may be painless and speedy.