what incident start the story?

Men in a war camp debate the accuracy of a rumor than one of the men has heard that they will be going to to battle on the next day. The debate turns loud and boisterous. The men end up in an argument and one of the men call Conklin a liar.

The story begins with a group of men standing (sitting) around, ruminating over whether they'll be going to battle soon. We're in the time period of the Civil War, and the men are anxious to get into battle, and yet believe that it will never really happen. The scene then move to Henry (main character) and a scene with his mother where he tells her he's going to join in the war effort.