Garmouth, the setting for The Machine Gunners, is also the setting for two other of Robert Westall's novels. The Watch House is a ghost story about a young girl, Anne, who spends the summer with her mother's old nannie. Fathom Five is another war story featuring Chas McGill, Audrey, and Cem. The plot focuses on their search for a German spy. Chas McGill also reappears in another World War II setting in a book of short stories named after him: The Haunting of Chas McGill and Other Stories. Here Chas discovers the ghost of an AWOL soldier from World War I and helps the soldier escape from a dismal fate.