Gertrude Sanford Legendre belonged to that class of people who never, ever do their own laundry. The title of “adventuress” fit her all too well — a crack shot with an unlimited budget, “Gertie” used her fortune to hunt the world for museum specimens, gunning down lions, tigers and other creatures now teetering on the edge of extinction. At the end of one Gertie excursion, her young daughter, consigned to the care of a nanny, failed to recognize her.

Not an easy hero to warm up to, but in “A Guest of the Reich,” Washington Post national security editor Peter Finn creates a compelling story from the strangest chapter in Legendre’s life: her capture by the German Army in the waning days of World War II and her dramatic escape from Nazi Germany.

Legendre’s prewar life was one of self-generated adventure. She traveled, partied and tended to the South Carolina plantation she owned with her husband, Sidney. With the advent of the war, Gertie and Sidney pursued their adventure addiction through war work. Sidney joined the Navy; Gertie went to Washington to join the Office of Strategic Services, precursor to the CIA. Through connections and relentless badgering, she was transferred to London and a key administrative position within the OSS.

After the liberation of Paris, Gertie wangled a French posting. On a lark she, an OSS colleague, an Army officer and their driver made a day trip to the Allied front, imagining, in the OSS officer’s words, that they would “mosey up to the line so the lady could hear some gunfire.” But their destination had shifted back to German control. The four Americans were strafed by German fire, wounding two of them. They became POWs, and Legendre became the first American woman in uniform to be captured by the Nazis.

So began an odyssey out of an Alan Furst novel, with echoes of “The Grand Budapest Hotel.” She began in a filthy solitary cell but was eventually shifted to a castle for high-class French prisoners, then to a German industrialist’s estate. The Germans knew they were losing, and they held Gertie as a bargaining chip.

Unknown to the Nazis, she was much more — she had acquired “a tremendous fund of information concerning OSS operations in the European theater,” wrote OSS head William Donovan. She could have been tortured and shot. But Gertie played the airhead heiress role to the hilt.

In her final days of captivity, she witnessed the Allied bombing of German cities, and through her eyes Finn vividly re-creates the apocalyptic landscape and the desperation of the German people. As the war winds down, the suspense ratchets up. Finn tells Gertie’s story with irony, humor and detail — the first thing Gertie got rid of after her escape was her orange Gestapo-issued underwear.

Legendre is a flawed hero, but Finn’s narrative is a vivid chronicle of the waning days of Nazi Germany, when a country answered for its own hubris and one American woman witnessed the nightmare.

A Guest of the Reich By: Peter Finn. Publisher: Pantheon, 256 pages, $27.95.

Mary Ann Gwinn is former books editor of the Seattle Times and a member of the National Book Critics Circle board.