One day in post-Brexit, mid-pandemic Britain, artist Sandy Gray receives an unexpected phone call from university acquaintance Martina Pelf. Martina is calling Sandy to ask for help with a mysterious question she's been left with after she's spent half a day locked in a room by border control officials for no reason she can fathom: 'Curlew or curfew? You choose.' And what's any of this got to do with the story of a young and talented blacksmith hounded from her trade and her home more than five hundred years ago? Ali Smith's novel takes wing, soaring between our atomised present and our medieval past in the hope we can open our locked down homes and selves to all the other times, other species, other histories, other possibilities.