Meet the Williamson sisters, Britain's most treasured World War II veterans. Now in their late nineties, Josephine and Penny are in huge demand, popping up at commemorative events and history festivals all over the country. Despite their age, they're still in great form--perfectly put together, sprightly and sparky, and always in search of their next "excitement."

This time it's a trip to Paris to receive the Légion d'honneur for their part in the liberation of France. And as always, they will be accompanied by their devoted great-nephew, Archie.

Keen historian Archie has always been given to understand that his great aunts had relatively minor roles in the Women's Royal Navy and the First Aid Nursing Yeomanry, but that's only half the story. Both sisters are hiding far more than the usual "official secrets". There's a reason sweet Auntie Penny can dispatch a would-be mugger with an umbrella.

This trip to Paris is not what it seems either. Scandal and crime have always quietly trailed the Williamson sisters, even in the decades after the war. Now armed with new information about an old adversary, these much decorated (but admittedly ancient) veterans variously intend to settle scores, avenge lost friends, and pull off one last, daring heist before the curtain finally comes down on their illustrious careers.