Ambrose Bierce A Horseman in the Sky

In 1913, Bierce traveled to Mexico to gain first-hand experience of the Mexican Revolution. While traveling with rebel troops disappeared in Mexico in 1914 without a trace and his final fate is unknown.

This is a little story is taking place during the American Civil War. The central character is a young Virginian, named Carter Druse, who decides to fight for the Union, betraying his state. He finds himself unavoidably having to kill a Confederate horseman spy turned out to be his own father. The story cycles around the considerations and feelings of this young man including conflicts with himself and reality.