Answer:
Bravery is doing something even when it scares you. Bradbury's setting of the night before the Battle of Shiloh helps him explore this question because at the beggining of the story the main charcter Joby is interested in joining the war as a drummer boy but he doesnt think he can do it. He finds that in the second part of the story the General comforts Joby and asks him to lead the army through the war, learning what bravery is and deciding to be brave.