Toby Cynster is not amused when informed that his new mission is to be his last in the shadowy service of Drake, Marquess of Winchelsea. Courtesy of Toby being the last unmarried Cynster of his generation and the consequent martial obsession of his female relatives, he will be given no more excuses to avoid society and, instead, expected to devote himself to finding a suitable bride. But Toby sees no point in marrying-thanks to his siblings, he has plenty of nephews and nieces with whom to play favorite uncle, and he has no thoughts of establishing a family of his own.

But then the mission takes an unexpected turn, leaving Toby to escort the irritatingly fascinating Diana Locke plus the three young children of a dying Englishman from Vienna to England.

Diana is no more enthused about their journey than Toby, but needs must, and forever practical, she bows to events and makes the best of things for her godchildren's sakes. She's determined to see them to safety in England and does her best to ignore her nonsensical and annoying awareness of Toby.

But then their journey becomes a flight from deadly pursuit, and their most effective disguise is to pass themselves off as a family-the sort of family Toby had been certain he would never want. Through a succession of fraught adventures, Toby, Diana, and the children lean on each other and grow and mature while furthering their ultimate aim of reaching England safely, and along the way, Toby and Diana both learn what having a family actually means to them, individually and together, and each discovers the until-then-missing foundation stone of their future lives.