Britten's operas often focus on the way particular worlds deal with an outsider. The outsider in Billy Budd is a young man, press-ganged into naval service on the HMS Idomitable around 1797. His story is told in an opera-length flashback by the ship's captain, Edward Fairfax Vere, who is racked by guilt over Billy's fate. Billy's optimism, good-heartedness and trusting nature wins over all but the most venal of the downtrodden crew. He's keen for promotion, but his charisma and beauty cause the evil master-at-arms, John Claggart (who resembles Iago in Shakespeare's Othello), to plot his destruction.

Billy's fatal flaw is that, under pressure, he suffers from a crippling stutter. When Claggart falsely accuses him of fomenting mutiny, in front of a sceptical Vere, Billy cannot find the words to defend himself and strikes Claggart dead. At the subsequent court-martial, Vere must follow the letter of the Articles of War and Billy is condemned to death. Typically, just before his execution, Billy cries out in praise of Vere. Now a very old man, Vere concludes that Billy's blessing has, in fact, saved him.