The Alice network / Kate Quinn.

"It's 1947 and American college girl Charlie St. Clair is pregnant, unmarried, and on the verge of being thrown out of her very proper family. She's also nursing a fervent belief that her beloved French cousin Rose, who disappeared in Nazi-occupied France during the war, might still be alive somewhere. So when Charlie's family banishes her to Europe to have her "little problem" take care of, Charlie breaks free and heads to London determined to find out what happened to the cousin she loves like a sister. In 1915, Eve Gardiner burns to join the fight against the Germans and unexpectedly gets her chance to serve when she's recruited to work as a spy for the English. Sent into enemy-occupied France during The Great War, she's trained by the mesmerizing Lili, the "Queen of Spies", who manages a vast network of secret agents, right under the enemy's nose. Thirty years later, haunted by the betrayal that ultimately tore apart the Alice Network, Eve spends her days drunk and secluded in her crumbling London house. Until a young American barges in uttering a name Eve hasn't heard in decades, and launching them both on a mission to find the truth ...no matter where it leads"--