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 following 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, while shining shoes at King's Cross Station, Alfie unexpectedly sees his father's name - on a sheaf of papers belonging to a ...