Although it takes Delano some time to unravel the situation, eventually he saves the title character, who is the captain of the slaver, and his remaining crew, and the leaders of the insurrection are slaughtered.  
It is narrated by Amasa Delano, the captain of a seal-hunting ship who encounters off the coast of Chile a slave ship whose human cargo has revolted.  Although it takes Delano some time to unravel the situation, eventually he saves the title character, who is the captain of the slaver, and his remaining crew, and the leaders of the insurrection are slaughtered.  FTP, identify this short story published in Putnam's Monthly Magazine in 1855 and later included in the collection The Piazza Tales, written by Herman Melville.
It is narrated by Amasa Delano, the captain of a seal-hunting ship who encounters off the coast of Chile a slave ship whose human cargo has revolted.  
Benito Cereno