I was looking forward to seeing Sam Mendes’s film “1917” when it arrived in theaters in December. I have a special interest in the subject — my grandfather fought in World War I, and I’ve done years of research on the events while writing a play about the war.

I can’t argue with Mr. Mendes’s artistry. Visually and technically speaking, “1917,” which is nominated for 10 Academy Awards, is dazzling. The filmmaking team cleverly manages to make the entire movie seem like one long, continuous take, and I, like many viewers, found myself wondering how certain scenes were shot.

The director’s own grandfather inspired him with stories about volunteering to run messages across open, war-ravaged terrain. In an interview, Mr. Mendes said that “1917” called for “a different kind of storytelling.” He described the “Great War” as “a chaos of mismanagement and human tragedy on a vast scale.”

If only he had told that story. Instead, “1917” left me uneasy. Mr. Mendes paints an uplifting and dangerously misleading picture of the war.

The fictionalized premise is this: General Erinmore (Colin Firth) sends two British soldiers on an urgent mission. They have until dawn to deliver a vital message: The Second Battalion is about to walk into a trap, and the attack must be called off. The general warns one of the soldiers, Lance Corporal Blake (Dean-Charles Chapman), “If you don’t get there in time, we will lose 1,600 men — your brother among them.”