It is 1945, and London is still reeling from the Blitz and years of war. Fourteen-year-old Nathaniel and his older sister, Rachel, are seemingly abandoned by their parents, left in the care of an enigmatic figure they call The Moth. They suspect he may 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? And how should the siblings feel when their mother returns without their father after months of silence, explaining nothing, excusing nothing? A dozen years later, Nathaniel begins to uncover all he didn't know or understand during that time, and it is this journey -- through reality, recollection, and imagination -- that is told.