Twelve Years a Slave
Northup is taken south on a boat.  Some of the other captives have been slaves all their lives, but others are kidnapped free men like Northup.  Some of them plan to take over the boat and escape, but then they get sick and cannot.  Northup, who can read and write, writes a note to a white friend in New York saying what has happened to him.  One of the sailors promises to mail it for him.