Shortlisted for the Costa Novel Award 2019. Tobi and Ella's childhood in East Berlin is shrouded in mystery. Now adults living in London, their past is full of unanswered questions. Both remember their family's daring and terrifying attempt to escape. But what happened next? Where did their parents disappear to , and why? What happened to Heiko , their little brother? And was there ever a painting of three blue horses? In contemporary Germany, Aaron works for a Stasi archive, making his way through old files, reconstructing the tragic history of thousands of families. But one file in particular catches his eye; and soon unravelling the secrets at its heart becomes an obsession. When Ella finds a stash of her mother's notebooks, she and Tobi embark on a search that will take them back to Berlin. Her fate clashes with Aaron's, and they piece together the details of Ella's past...