August 1989. Septuagenarian Lillian de la Pérouse is presumed dead, leaving her estate to her American nephew, Carl Box. Carl, who knows Lily only as a mysteriously disgraced relative, arrives in Paris with his faithful companion, a disabled dog named Billy. To his astonishment, he discovers his aunt to be alive and evading an unknown killer.
Lily, a former Dior model and small press publisher, has been smuggling top-secret KGB archives from Moscow to Paris. Lily uses Carl’s arrival to lend credibility to her faked death, introducing him to her team of eccentric misfits and sending him on missions in her stead. Along with a beautiful activist Carl recruits along the way, they race through the enchanting streets of Paris, from the bustling markets of the Marais to the romantic banks of the Seine, trying to stay one step ahead of foreign agents, a French detective, and everyone else vying for the files.
As Lily introduces her nephew to her high-stakes world and teaches him the art of living, Carl finds himself transformed by the adventure, by Paris, by romance, and by the ever-growing bond between himself and his unconventional Aunt Lily.
But why did Lily disappear all those years ago? What secrets is she hiding? And who is she, really?