Part of a stunning new design partnership between Puffin and the Imperial War Museum, from the bestselling author of The Boy in the Striped Pyjamas. The day the First World War broke out, Alfie Summerfield’s father promised he wouldn’t go away to fight - but he broke that promise the very next day. Four years later, Alfie doesn’t know where his father might be, other than that he’s away on a special, secret mission. Then a chance encounter at King’s Cross Station offers hope - Alfie realises his father is in a hospital close by - and Alfie becomes determined to rescue his father from this strange, unnerving place …