It is 1945, and London is still reeling from the Blitz and years of war. 14-year-old Nathaniel and his sister, Rachel, are apparently abandoned by their parents, left in the care of an enigmatic figure named The Moth. They suspect he might be a criminal, and grow both more convinced and less concerned as they get to know his eccentric crew of friends: men and women with a shared history, all of whom seem determined now to protect, and educate (in rather unusual ways) Rachel and Nathaniel. But are they really what and who they claim to be? A dozen years later, Nathaniel begins to uncover all he didn't know or understand in that time, and it is this journey - through reality, recollection, and imagination - that is told in this magnificent novel.