RUTHFULLY YOURS

She was a woman, he said. France was no place for her. Would she like to go dancing with him in Gibraltar instead?

Sansom was relentless. She would get there even if she had to swim, she told him. He commented that she would look good in a bathing suit. In the end, she did the only thing she could—she got him so drunk that he gave in.

Odette Sansom, née Brailly, would go on to become the most decorated woman of World War II—a member of the Order of the British Empire, a Chevalier de la Légion d’honneur, and the first woman awarded the George Cross, an award for “acts of the greatest heroism.” Her story was first told in print in 1949, followed by a film re-enactment the next year that made her a national heroine. It has been retold many times since. In “Code Name: Lise,” Larry Loftis tells it again for a new generation, reweaving the usual account of her wartime activities into a kind of nonfiction thriller.

It is a story that is inherently thrilling. “Shortly after ten the mist began to dissipate,” Mr. Loftis begins, “leaving them partially exposed.” He then flashes back to give a glimpse of Sansom’s childhood. Born in Amiens, France, she grew up visiting her father’s grave every Sunday with her brother and grandparents. A war hero, he had been killed in action when she was 6. When war returns, her grandfather said, it will be your duty to do as well as your father did.

Sansom suffered various illnesses in childhood, including a bout of polio that blinded her for three years—an experience that braced her for the trials to come. At 18, she married an Englishman, Roy Sansom, and moved to England. In 1942, when the Admiralty asked civilians to send in photos of the French coastline for possible war use, Sansom mistakenly sent hers to the War Office. That was how she came to the attention of Col. Maurice Buckmaster of the Special Operations Executive (SOE), a sabotage and espionage outfit formed in 1940. Its mission, according to Winston Churchill, was to “set Europe ablaze.” Nicknamed the Baker Street Irregulars, due to the location of its London headquarters, the group was also known by other names—“The Ministry of Ungentlemanly Warfare” and “Churchill’s Secret Army.”

Buckmaster was particularly interested in finding recruits who could pass as locals. Sansom’s native French made her a natural asset, but she was initially considered too temperamental to serve. “She is impulsive and hasty in her judgments,” read one evaluation, “and has not quite the clarity of mind which is desirable in subversive activity.” It also noted, however, her “patriotism and keenness to do something for France.” Despite these reservations, the SOE sent her on. She made contact with Peter Churchill, an officer who headed a network of agents based in Cannes, and began acting as his courier, running messages around the south of France. In a stroke of unbelievably bad luck, another agent fell asleep on a train while carrying a briefcase containing a list of 200 agent names. When he woke up, the briefcase was gone. The list made its way into the hands of Hugo Bleicher, the Germans’ master spy-catcher, who soon infiltrated the network.

Sansom and Peter Churchill were arrested in April 1943 and sent to Fresnes Prison, outside of Paris. She was interrogated by the Gestapo 14 times and tortured, her back scorched with a red-hot poker and all of her toenails pulled out. Still, she refused to disclose the locations of other agents. She deflected attention from Peter, claiming to be the brains of the operation, and also cleverly made use of his famous name. Though Peter was not related to the great prime minister, Sansom said he was—and that she was his wife. That ruse is almost certainly what saved both of their lives. She was condemned to death on two counts. (“Gentlemen, you must take your pick of the counts,” she retorted. “I can only die once.”) The order was never carried out. Even the Nazis were hesitant to execute relatives of Winston Churchill. Instead, she was sent to rot in a solitary cell at the Ravensbrück concentration camp.

Mr. Loftis’s writing is frequently difficult to tolerate. He takes a story that is already dramatic and tries to make it more so with cheesy coats of romance and horror. Peter, who married Odette after the war, gazes into her eyes: “Immediately he was swimming—swimming in her love, in the embrace that was there, in the promise that if he returned, she would be his.” Then he walks, predictably, into a “moon-swept night.” Later they shuffle together “through the valley of the shadow of death.”

Fortunately, febrile prose can’t undercut the sheer power of Sansom’s story and of Sansom herself. In later years, critics of SOE maligned her, claiming that she’d spent the war in bed with Peter, that she’d made up her stories of torture, and that she’d survived Ravensbrück by sleeping with the camp commandant. Medical records and the testimony of other agents proved otherwise, but those files remained classified for years. It was her word against theirs. Though she and Churchill later divorced, he never stopped defending her. “I have never known such a brave woman.”

—Ms. Winkler is a writer for the Journal’s Heard on the Street column.