When their father's death leaves them impoverished, Sarah Summers and her genteel sisters fear they will be forced to sell the house and separate to earn livelihoods as governesses or companions. Determined to stay together, Sarah convinces them to open their seaside home to guests to make ends meet and provide for their ailing mother. Instead of the elderly invalids they expect to receive, however, they find themselves hosting eligible gentlemen. Sarah is soon torn between a growing attraction to a mysterious Scottish widower and duty to her family.

Three years into the Great War, England's greatest asset is their intelligence network - field agents risking their lives to gather information, and codebreakers able to crack every German telegram. Margot De Wilde thrives in the environment of the secretive Room 40, where she spends her days deciphering intercepted messages. But when her world is turned upside down by an unexpected loss, for the first time in her life numbers aren't enough.

In 1942, Evie Farrow is used to life on Ocracoke Island, where every day is the same—until the German U-boats haunting their waters begin to wreak havoc. And when special agent Sterling Bertrand is washed ashore at Evie's inn, her life is turned upside down. While Sterling's injuries keep him inn-bound for weeks, making him even more anxious about the man he's tracking, he becomes increasingly intrigued by Evie, who seems to be hiding secrets of her own.

Miss Gwendolyn Brinley accepted a temporary paid companion position for the Newport summer season, believing it would be a lark to spend the summer in America's most exclusive town. She suddenly finds her summer turning anything but amusing when her employer expects her to take over responsibilities as an assistant matchmaker. Tasked with the daunting prospect of attaining advantageous matches for her clients, Gwendolyn soon finds herself in the company of Mr. Walter Townsend, the catch of the Season, but a gentleman Gwendolyn finds beyond annoying.

Miss Isadora Delafield may be an heiress, but her life is far from carefree. When her mother begins pressuring her to marry an elderly and uncouth duke, she escapes from the high-society world she's always known and finds herself to be an unlikely candidate for a housekeeper position in rural Pennsylvania. Mr. Ian MacKenzie is known for his savvy business sense and has built his reputation and fortune completely on his own merits. But when his adopted parents are in need of a new housekeeper and Isadora is thrown into his path, he's unexpectedly charmed by her unconventional manner.