Showing The Girl Below by Bianca Zander

After ten years in New Zealand, Suki returns to London, to a city that won’t let her in. However, a chance visit with Peggy – an old family friend who still lives in the building where she grew up – convinces Suki that there is a way to reconnect with the life she left behind a decade earlier. But the more involved she becomes with Peggy’s dysfunctional family, including Peggy’s wayward sixteen-year-old grandson, the more Suki finds herself mysteriously slipping back in time – to the night of a party her parents threw in their garden more than twenty years ago, when something happened in an old, long-unused air-raid shelter…