Drawing on Barry McCrea’s work on Arthur Conan Doyle, this article challenges claims that the interwar country-house mystery arose from reactionary nostalgia for a “dead” institution. Responding not to a sudden death but to a slow decline, the form in fact facilitated the country house’s reconfiguration as a biologically sterile but narratively generative queer space. This war has filled England with strangers, with men and women from far away, who may not for years have seen the faces they love. . . . We, whose English homes mean so much to us—let us make it the rule that . . . there shall be no strangers. . . . What is home? Must it be a narrow place, from which the family bars out the world’s troubles, ignoring these in a happiness all its own? Surely not. . . . It is true that we turn to home for its quiet, its privacy, its uniqueness. All the same, we go wrong if we do not realise that home—each home—is a living, organic part of the world. (Bowen 21; emphasis in original) Writing in 1942, at the height of war on the homefront, Elizabeth Bowen was peculiarly well placed to voice this plea for openness: an Anglo-Irish “stranger” in England, and a prolific essayist and social commentator, she was also a proponent of the “middlebrow” novel for whom houses were always particularly “ambivalent spaces” (Humble 63). The mid-century middlebrow novel was a form marked by “its overriding concern with the home” (Humble 5), and although it may have taken a second war to prompt so explicit a reimagining of domestic space in the popular press, the implications of this reimaging had been playing out in Bowen’s fictional houses and those of her contemporaries since World War I. Nowhere was this more prominent than in the ubiquitous country houses of interwar mystery fiction—as exemplified by, although by no means limited to, Agatha Christie— which exposed the narrative possibilities of a queer new spatial order.