London, 1941. Amongst the air-raid sirens and horrors of bombings, artist Harriet Yorke manages Calla House: a small community of people from different backgrounds but good friends who pull together in times of crisis. Like most Londoners contending with the Blitz, Harriet has grown used to withstanding danger, but when she goes on a late-evening stroll with her Cairn Terrier, George, and finds herself face to face with a killer, she unleashes a series of events that will put more than just her own life on the line. London, 2019. Libby lives amongst her grandmother’s paintings in Calla House, works of art into which Harriet poured all the horror of her wartime experiences, culminating in that one terrifying night. Libby’s Calla House is a comfortable safe haven for her and its other residents until, that is, a crumbling chimney pot sparks an alert. Libby calls in builders, but as her troubles magnify, she begins to wonder if the ghosts of Harriet’s past aren’t going to bring more than the house down around her ears.