Brook Eden has never known where she truly belongs. Though raised in the palace of Monaco, she's British by birth and was brought to the Grimaldis under suspicious circumstances as a babe. When Brook's friend, Justin, uncovers the fact that Brook is likely a missing heiress from Yorkshire, Brook leaves the sun of the Mediterranean to travel to the moors of the North Sea, to the estate of her supposed family.

Left with an estate on the brink of bankruptcy after their father's death, Lady Marigold Fairfax and her brother open a private investigation firm marketed to the elite . . . to spy on the elite. Dubbed The Imposters, Ltd., their anonymous group soon becomes the go-to for the crème of society when they want answers delivered surreptitiously. But the many secrets Marigold learns about her peers pale in comparison to her shock when she and her brother are hired to investigate her best friend's father as a potential traitor.

1906: Lady Elizabeth “Libby” Sinclair, with her love of microscopes and nature, isn’t favored in society. She flees to the beautiful Isles of Scilly for the summer and stumbles onto the dangerous secrets left behind by her holiday cottage’s former occupant, also named Elizabeth, who mysteriously vanished. Oliver Tremayne - gentleman and clergyman - is determined to discover what happened to his sister, with the help of the girl now living in what should have been Beth’s summer cottage...especially when he realizes it’s the curious young lady he met briefly two years ago.

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.

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.