The Walls of Cartagena

The Walls of Cartagena by Julia Durango, illustrated by Tom Pohrt
Thirteen-year-old Calepino, an African slave in the seventeenth-century Caribbean city of Cartagena, works as a translator for a Jesuit priest who tends to newly-arrived slaves and, after working for a Jewish doctor in a leper colony and helping an Angolan boy and his mother escape, he realizes his true calling.