From Royal Opera House website:
Three new recruits join the warship HMS Indomitable, commanded by the scholarly Captain Vere. The first two are nothing special, but the third, young Billy Budd, is hailed by the Master at Arms John Claggart as a jewel - despite his occasional stammer. Billy settles in happily as foretopman and his kindness quickly makes him friends.
However, Billy's goodness has also inspired the tormented Claggart to hatred, and he vows to destroy him. He fabricates evidence that Billy plans to lead the ship's crew in a mutiny, then accuses Billy in front of Captain Vere. Billy is stunned, and reacts violently and with devastating consequences.