The breath-taking new novel from the author of The Tattooist of Auschwitz and Cilka's Journey, based on a powerful true story of hope and survival.

'I want you to make a promise to me that you will always take care of your sisters. That you will always be there for one another. That you will not allow anyone to take you away from each other, ever. Do you understand?'

When they are little girls, Cibi, Magda and Livia make a promise to their father - that they will stay together, no matter what. Years later, at just 15, Livia is ordered to Auschwitz by the Nazis. Cibi, only 19 herself, remembers their promise and follows Livia, determined to protect her sister, or die with her. Together, they fight to survive through unimaginable cruelty and hardship.

Magda, only 17, stays with her mother and grandfather, hiding out in a neighbour's attic or in the forest when the Nazi militia come to round up friends, neighbours and family. She escapes for a time, but eventually she too is captured and transported to the death camp.

In Auschwitz-Birkenau the three sisters are reunited and, remembering their father, they make a new promise, this time to each other: That they will survive.