The Captain and the Enemy by Graham Greene
Victor Baxter is a young boy when a secretive stranger known simply as "the Captain" brings him from his boarding school to London. Victor becomes the surrogate son and companion of a woman named Liza, who renames him "Jim" and depends on him for any news about the world outside their door. Raised in these odd yet touching circumstances, Jim is never quite sure of Liza’s relationship to the Captain, who is often away on mysterious errands. It is not until Jim reaches manhood that he confronts the Captain and learns the shocking truth about the man, his allegiances, and the nature of love.