It is the summer of 1919 and Constance Haverhill is without prospects. Now that all the men have returned from the front, she has been asked to give up her cottage and her job at the estate she helped to run during the war. While she looks for a position as a bookkeeper or (horror) a governess, she's sent as a lady's companion to an old family friend who is convalescing at a seaside hotel. Despite having only weeks to find a permanent home, Constance is swept up in the social whirl of Hazelbourne-on-Sea and its colourful inhabitants, most notably, Poppy Wirrall. Poppy, the daughter of a land-owning baronet, wears trousers, operates a taxi and delivery service to employ local women and runs a ladies' motorcycle club (to which she plans to add flying lessons). She and her friends enthusiastically welcome Constance into their circle.