Orphan, clock keeper, and thief, twelve-year-old Hugo lives in the walls of a busy Paris train station, where his survival depends on secrets and anonymity. But when his world suddenly interlocks with an eccentric girl and the owner of a small toy booth in the train station, Hugo's undercover life, and his most precious secret, are put in jeopardy. A cryptic drawing, a treasured notebook, a stolen key, a mechanical man, and a hidden message all come together to change Hugo's life forever.