Military prosecuter Captain Hargraeves is ordered to put private Arthur Hamp on trail for desertion during battle. During the interrogation he discovers that the accused is simple, slow-witted man. Hamp, a working class soldier, had to leave school at the age of 12 so he could join the family’s boot-making business. He enlisted only because his mother-in-law and his wife insisted. After having served three years in the trenches he is last one alive of his enlistment. When he receives a goodbye-letter from his wife and a friend standing next to him is killed by a shell during the battle of Passchendaele, he decides to „Walk away from the guns“ home to England. He is arrested by the MP near Calais and charged with desertion. The longer the trial lasts, the more Hargreaves is convinced that Hamp is innocent and should be released on the grounds of shell shock, a diagnose Dr. O’Sullivan refuses to attest. In the end Hamp has to return to the front where he is shot during the next offensive.